Mental Arithmetic

Question No 1

A motorcyclist travels 200 Km in 1 hr. How many minutes if would take him to travel 120 Km?

Select the correct answer

72 50 36 24

Solution!
200 Km distance covered in minutes = 60

1 Km distance covered in minutes = 60/200 = 3/10

120 Km distance covered in minutes = (3/10) * 120 = 36 minutes.

Question No 2

2664/12/6=?

Select the correct answer

43 41 37 33

Solution!
(2664/12) * (1/6) = 37.

Question No 3

What is 8/40 expressed as a decimal?

Select the correct answer

1.0 0.6 0.2 0.5

Solution!
Simple way is

(8/4) * (1/10) = 2 * 0.1 = 0.2.

Question No 4

John can read 8 pages of a book in 7 minutes, how long will he take to read 40 pages?

Select the correct answer

30 min 35 min 40 min 45 min

Solution!
40/8 = 5

As pages are increased 5 times. So minutes will also increase 5 time.

7 * 5 = 35.

Question No 5

If the number 5r2 is divisible by 6, then r = ?

Select the correct answer

2 7 3 5

Solution!
572 is completely divisible by 6..

Question No 6

What must be added to each numerator and denominator of 13/29 so that it becomes 1/2

Select the correct answer

9 3 8 none

Solution!
(13+3)/(29+3) = 1/2.

Question No 7

At a particular time shadow of a pole 40m long is measured to be 30m. If the length of a plaza is 200m then how long would the shadow be at about the same time?

Select the correct answer

180 100 150 120

Solution!
Shadow of 40m pole = 30m

Shadow of 1m pole = 30/40m

Shadow of 200m plaza = (30/40)*200 = 150m.

Question No 8

Subtract 369 from 1250.

Select the correct answer

881 900 960 985

Solution!
1250 - 369 = 881.

Question No 9

If n is not equal to 0, Which of the following must be greater than n? (1) 2n (2) n^2 (3) 2-n

Select the correct answer

(1) only (2) only (1) and (2) (2) and (3)

Solution!
Square of every non zero integer is grater than the orignal number.

*Note that multiple of 2 of negative numbers are lesser than the orignal number..

Question No 10

If the number 481z673 is completely divisible by 9, what is the the smallest whole number in place of z?

Select the correct answer

3 7 5 9

Solution!
Select answer from options

4817673 is completely devisible by 9..

Question No 11

Deduct 7.3 from 34.2.

Select the correct answer

27.2 27 26.9 28

Solution!
34.2 - 7.3 = 26.9.

Question No 12

100/101 = ?

Select the correct answer

0.99 1.11 1 0

Solution!
100/101 = 0.990099.

Question No 13

What is 10 less 5/9 of 117?

Select the correct answer

65 55 60 70

Solution!
(5/9) * 117 = 65

65 - 10 = 55.

Question No 14

Divide 672 by 12.

Select the correct answer

68 65 67 56

Solution!
672 / 12 = 56.

Question No 15

The side of a square is 2. What is the area of the square?

Select the correct answer

4 8 16 2

Solution!
Area of square is
2 * (any side)
= 2 * (2) = 4 square units.

Question No 16

The average weight of 16 boys in a class is 50.25 kg and that of the remaining 8 boys is 45.15 kg.Find the average weights of all the boys in the class.

Select the correct answer

48.55 42.25 50 51.25

Solution!

In this question weighted average is calculated rather than simple average

(50.25*16 + 45.15*8)/(16+8) = 48.55.

Question No 17

If the product of 4 consecutive integers is 120, which is greater?

Select the correct answer

5 7 9 can't be determined

Solution!
5*4*3*2 = 120.

Question No 18

7/21 in lowest term is?

Select the correct answer

1/3 7/21 14/42 None of these

Solution!
7/21 = 1/3.

Question No 19

If average of 8, 7, 12, 15 and x is 11 what is x?

Select the correct answer

10 13 11 12

Solution!
(8+7+12+15+x)/5 = 11

42+x = 55

x = 55-42
=13.

Question No 20

The average of five numbers is 27.If one number is excluded the average becomes 25.What is the excluded number?

Select the correct answer

30 40 35 32.5

Solution!
No answer description available for this question..

Question No 21

Divide 52 by 4 and add 17 multiplied by 3.

Select the correct answer

64 66 62 60

Solution!
52 / 4 = 13

17 * 3 = 51

13 + 51 = 64.

Question No 22

What is 126 divided by 3?

Select the correct answer

41 43 42 44

Solution!
126 / 3 = 42.

Question No 23

If n is even, Which of the following cannot be odd? (1) n+3 (2) 3n (3) n^2 - 1

Select the correct answer

(1) only (2) only (3) only (1) and (2)

Solution!
3n and n^2 - 1 will always odd so in case of 3n answers will be even..

Question No 24

A number is thrift if it is a multiple of 2 or 3. How many thrift numbers are there between 0 and 15?

Select the correct answer

8 11 15 9

Solution!
Thrift numbers between 0 and 15 are following

2,3,4,6,8,9,10,12,14.

Question No 25

If the sum of three consecutive whole numbers is 15, what is the largest of the three numbers?

Select the correct answer

9 8 5 6

Solution!
6+5+4 = 15.

Question No 26

Ali can type at a speed of 25 words per minute. How many words he can type in one hour?

Select the correct answer

1300 1200 1500 1475

Solution!
Typed words in 1 minute = 25
Typed words in 60 minutes = 60 * 25 = 1500.

Question No 27

16 men dig a ditch in 10 days. How many men would be required to complete the job in half the time?

Select the correct answer

8 32 24 20

Solution!
Double number of men are required to complete the job in half time..

Question No 28

What is average of 12 , 15 and 18?

Select the correct answer

10 12 13 15

Solution!
(12+15+18)/3 = 45/3 = 15.

Question No 29

What is 3206 divided by 7?

Select the correct answer

352 548 458 558

Solution!
3206 / 7 = 458

No need to perform complete devision first digit comes 4 after devision and there is only one option in which first digit is 4..

Question No 30

Which is greater, (A) 5/8 of 112 , (B) 7/8 of 88?

Select the correct answer

B A Both Nothing

Solution!
(5/8) * 112 = 70

and
(7/8) * 88 = 77

Hence, (7/8) of 88 is greater..

Question No 31

When R is divided by 7 remainder is 3. What is the remainder when 3R is divided by 7?

Select the correct answer

1 2 5 9

Solution!
No answer description is available for this question..

Question No 32

What is the difference of the product and the quotient of 8 and 8?

Select the correct answer

64 1 63 65

Solution!
8*8 = 64
and
8/8 = 1
So,
64 - 1 = 63.

Question No 33

What is the average of 8, 13, 25, 43, and 11?

Select the correct answer

20 32 27 19

Solution!
(8+13+25+43+11)/5 = 100/5
= 20.

Question No 34

Which of the following is the least number which is divisible by both 12 and 18?

Select the correct answer

36 30 72 78

Solution!
Least common multiple of 12 and 18 is 36.

Question No 35

What is average of 2, 5 , 6 , 9 and 18?

Select the correct answer

6 7 8 9

Solution!
(2+5+6+9+18)/5 = 40/5 = 8.

Question No 36

Which of the following is a prime number?

Select the correct answer

9 8 4 2

Solution!
A prime number is the number which is divisible by 1 and by itself only

and 2 is the only one even number which is prime..

Question No 37

What is 9 multiplied by 8?

Select the correct answer

64 84 72 74

Solution!
9 * 8 = 72.

Question No 38

A coach trip starts at nine fifty.It lasts twenty-five minutes.At what time does it finish?

Select the correct answer

ten twenty ten Fifteen ten thirty ten fourty

Solution!
No answer description available for this question..

Question No 39

Ahmad reads 24 pages of a book in 15 minutes. The rate of pages read per minute by him will be

Select the correct answer

1.6 2 2.5 3

Solution!
24/15 = 8/5
8/5 = 1.6.

Question No 40

A cycle costs $170.Jane saves $50 each week.How many weeks will it be before she can buy it?

Select the correct answer

10 20 15 4

Solution!
170 / 50 = 3.4
But 3.4 is not in options so nearest Option is 4.

Question No 41

If m is an even integer and 3m < 48 and 2m > 24 then m = ?

Select the correct answer

12 14 16 10

Solution!
3*14 = 42 (lesser than 48)
and
2*14 = 28 (greater than 24)..

Question No 42

Multiply 15 by 6 and subtract 29.

Select the correct answer

57 63 61 59

Solution!
15 * 6 = 90

90 - 29 = 61.

Question No 43

Add 2/5 of 90 to 5/6 of 78.

Select the correct answer

101 110 111 91

Solution!
(2/5) * 90 = 36

(5/6) * 78 = 65

36 + 65 = 101.

Question No 44

How much is 25% of $200?

Select the correct answer

$25 $50 $75 $100

Solution!
25 * (200/100) = $50

Or
200 / 4 = $50.

Question No 45

In a class the ratio of boys to girls is 1/3. What percent of students are girls?

Select the correct answer

40% 45% 25% 75%

Solution!
Percentage of girls in class = (3/4)*100 = 75%.

Question No 46

If x = 8*89 and y = 8*85, What is the value of x-y ?

Select the correct answer

32 8 4 116

Solution!
(8*89) - (8*85)
=8*(89 - 85)
=8*(4)=
32.

Question No 47

What is 5.9 + 6.8 + 7.34?

Select the correct answer

20 20.04 22.06 21.04

Solution!
6.8 + 7.34 = 14.14

14.14 + 5.9 = 20.04.

Question No 48

What is the cost of three tapes at $1.99 each?

Select the correct answer

$5.97 $4.97 $3.97 $2.97

Solution!
1.99 * 3 = $5.97.

Question No 49

Multiply 694 by 11.

Select the correct answer

6684 6664 6000 7634

Solution!
694 * 11 = 7634

Quick way to find answer from options is

694 * 10 = 6940

So answer must be greater than 6940 and only one option is greater than 6940 which is 7634..

Question No 50

30 men can complete a work in 30 days how long will 20 men take to complete the same amount of work?

Select the correct answer

30 days 35 days 40 days 45 days

Solution!
x/30 = 30/20

x = (30/20)*30 = 45.

Question No 51

Which of the following is an integer that has a remainder of 1 when it is divided by 4,5 and 6?

Select the correct answer

51 61 41 47

Solution!
Least common multiple of 4,5 and 6 is 60 so 61 is an integer that has a remainder of 1 when it is divided by 4,5 and 6..

Question No 52

What is smallest integer greater than 1 that leaves remainder 1 when it is divided by 5 or 8?

Select the correct answer

31 41 11 21

Solution!
40 is the least common multiple of 5 and 8 so 41 will be the smalles integer that leaves 1 when it is divided by 5 or 8..

Question No 53

Sum of three consecutive odd integers is 51. Which of the following is the smallest of the three?

Select the correct answer

21 15 17 19

Solution!
19+17+15 = 51.

Question No 54

A/B = 2/3. If value of A is 8 What is the value of B?

Select the correct answer

8 10 12 15

Solution!
8/B = 2/3
2B = 24
B = 12

*In short-cut way We can find 2 is multiplied by 4 to get 8 so if we multiply 3 with 4 we get 12 which is the value b B when value of A is 8..

Question No 55

Which of the following fractions is closed to 0.5?

Select the correct answer

15/10 15/20 15/30 25/20

Solution!
15/30 = 1/2
1/2 = 0.5.

Question No 56

In the first 10 overs of a cricket game the run rate was only 3.2 What should be the run rate in the remaining 40 overs to reach the target of 282?

Select the correct answer

6.25 5.5 7.36 4.9

Solution!
3.2 * 10 = 32

After 10 overs score is 32.

Remaining score = 282 - 32 = 250

Required rate = 250 / 40 = 6.25 runs/over.

Question No 57

Which one of the following is a prime number ?

Select the correct answer

307 437 247 203

Solution!
307 is only number which is divisible by 1 and by itself only..

Question No 58

Divide 56 by 8 and add 17.

Select the correct answer

7 27 25 24

Solution!
56 / 8 = 7

7 + 17 = 24.

Question No 59

John's fail to pass ratio in mathematics test is 5/2. In how many tests did he pass if total tests conducted were 42?

Select the correct answer

12 30 22 40

Solution!
Pass ratio = (2/7)*42 = 12.

Question No 60

Add 32 + 8 + 18 + 25.

Select the correct answer

83 81 79 84

Solution!
32 + 8 = 40

40 + 18 = 58

58 + 25 = 83.

Question No 61

The average of 20 numbers is 0, How many of them may be greater than zero,at the most?

Select the correct answer

1 20 0 19

Solution!
Maximum Numbers that can be greater than 0 to maintain total average greater than 0 are 19..

Question No 62

35 Kg of spinach costs Rs. 28. How many Kg of spinach can be bought for Rs. 16?

Select the correct answer

28 20 35 15

Solution!
Amount of spinach which can be bought in Rs. 28 = 35 kg

Amount of spinach which can be bought in Rs. 1 = 35/28 = 5/4 Kg

Amount of spinach which can be bought in Rs. 16 =(5/4)*16 = 20 Kg.

Question No 63

Multiply 7 by 4 by 6.

Select the correct answer

170 168 158 178

Solution!
7 * 4 = 28

28 * 6 = 168.

Question No 64

Deduct 865 from 1063.

Select the correct answer

202 188 190 198

Solution!
1063 - 865 = 198.

Question No 65

What is 15 multiplied by 11?

Select the correct answer

175 165 163 171

Solution!
15 * 11 = 165.

Question No 66

If one third of the staff at school are teachers find the ratio between teachers to non-teachers.

Select the correct answer

2/3 2/1 1/2 3/2

Solution!
ratio of teachers = 1/3

ratio of non-teachers = 2/3

Ratio of teachers to non-teachers = (1/3) * (3/2) = 1/2.

Question No 67

Average of 4 numbers is 24. What is the sum of the four numbers?

Select the correct answer

6 48 96 240

Solution!
x/4 = 24
x = 24*4
x = 96.

Question No 68

What is 5/9 of 270?

Select the correct answer

145 150 140 160

Solution!
(5/9) * 270 = 150.

Question No 69

378 * ? = 252

Select the correct answer

2/3 3/4 1/2 None

Solution!
252 / 378 = 2/3.

Question No 70

15 weavers can weave some length of cloth in 1 hr. 24 minutes. How many more weavers are required to do the same job in 60 minutes?

Select the correct answer

6 21 25 30

Solution!
x/15 = 84/60

x = (84/60)*15 = 21

So 21 - 15 = 6 more weavers are required to do the same job in 60 minutes..

Question No 71

Multiply 72 by 15.

Select the correct answer

1110 1080 1040 1160

Solution!
72 * 15 = 1080

Other way is

72 * 10 = 720
and
720 / 2 = 360

720 + 360 = 1080.

Question No 72

Price of a mobile phone is Rs. 8,000. A man has enough money to purchase 3 mobiles. How many mobile can he purchase if the price is reduced by Rs. 2000?

Select the correct answer

5 4 3 2

Solution!
Minimum amount of money that he has = 8,000 * 3 = 24,000

If price is reduced to 6,000, he can purchase 24,000/6,000 = 4.

Question No 73

64% of the children in school are girls.What percentage are boys?

Select the correct answer

26% 24% 36% 34%

Solution!
100 - 64 = 36%.

Question No 74

In a box ratio of DVD to VCD is 2/3. Which of the following cannot be the total number of CD's in the box?

Select the correct answer

65 40 25 11

Solution!
As 2+3 = 5, So total number of CD's must be multiple of 5.

In the options all are multiple of 5 except 11

So 11 is the correct answer..

Question No 75

At an educational trip of a school ratio of boys to girls students was 4/5. how many students were on the tour?

Select the correct answer

80 90 70 50

Solution!
Data is insufficient for this problem. But we can find the answer from the options. As 4 + 5 = 9, So answer should be multiple of 9 to fullfil the condition of 4/5 ratio..

Question No 76

Multiply 7 by 12 and divide by 6.

Select the correct answer

14 13 16 15

Solution!
7 * 12 = 84

84 / 6 = 14.

Question No 77

Add 5683 to 1729 and divide by 2.

Select the correct answer

3460 3500 3494 3706

Solution!
5683 + 1729 = 7412

7412 / 2 = 3706.

Question No 78

If a amount of $120 is divided among A and B in the ratio 1/2 then A will get?

Select the correct answer

$30 $40 $60 $80

Solution!
A will get half amount which B got.So if A's amount is 40, B's amount will be 80 (double of A's amount)..

Question No 79

In a Zoo deers and lions are in ratio of 5/2. If there are 20 deers how many lion are there?

Select the correct answer

10 8 6 3

Solution!
20 is 4 times of 5 So in this way 4 times of 2 will be 8..

Question No 80

What is the largest 4 digit number exactly divisible by 88?

Select the correct answer

9944 9999 9988 9900

Solution!
No answer description available for this question..

Question No 81

49/10 + 49/10 + 49/10 = ?

Select the correct answer

147/30 137/10 149/30 147/10

Solution!
By taking LCM of these three terms we have

(49+49+49)/10 = 147/10.

Question No 82

Multiply 6.85 by 7.

Select the correct answer

47.95 41.4 42.9 40.95

Solution!
6.85 * 7 = 47.95.

Question No 83

What is 45% of 300?

Select the correct answer

155 149 151 135

Solution!
45 * (300/100) = 135

Quick way to find answer from options is

50% of 300 is 150 so 45% of 300 should be less than 150

So, it may be 149 or 135
149 is very close to 150 which is not possible

Hence, 135 is correct answer..

Question No 84

Average of 3 numbers is 15. What is the sum of 3 numbers?

Select the correct answer

45 36 5 10

Solution!
Let sum is x.

x/3 = 15
x = 15*3 = 45.

Question No 85

2+2*2?

Select the correct answer

8 10 4 6

Solution!
2 + (2 * 2) = 6

Multiplication is performed first and subtraction afterwards.

Sequence of solving operators is
/
*
+
-.

Question No 86

What is average of 2 , 5 and 8?

Select the correct answer

3 4 5 6

Solution!
(2+5+8)/3 = 15/3 = 5.

Question No 87

What is 5/8 of 240?

Select the correct answer

200 150 175 250

Solution!
(5/8) * 240 = 150.

Question No 88

What is the sum of first 5 positive even integers?

Select the correct answer

26 28 30 32

Solution!
2+4+6+8+10 = 30.

Question No 89

If the average marks of three batches of 55, 60 and 45 students respectively is 50, 55, 60, what is the average marks of all the students?

Select the correct answer

53.23 54.68 51.33 50

Solution!
Weighted average will be more close to the average of that batch which has maximum number of students so aanswer is 54.68

If you want to calculate it by formula then solution is

(55*50 + 60*55 + 45*60)/(55 + 60 + 45) = 54.68.

Question No 90

15 men were hired to plough a piece of land in 10 days. How many more men will be required to do the same job in 3 days?

Select the correct answer

35 40 50 30

Solution!
x/15 = 10/3

x = (10/3)*15
x = 50.

So more number of men required = 50-15 = 35.

Question No 91

What is 35% of 250?

Select the correct answer

87.5 103 97 55

Solution!
35 * (250/100) = 87.5

Quick way to find answer from options is

33% of 250 is nearly 83(250/3 = 83.3)

So, answer should be in 80's which is only one option 87.5.

Question No 92

Multiply 86 by 9 and add to 13 multiplied by 6.

Select the correct answer

852 850 844 860

Solution!
86 * 9 = 774

13 * 6 = 78

774 + 78 = 852.

Question No 93

If p is and odd integer and 7p > 50 and 3p < 35 then p is?

Select the correct answer

8 11 13 19

Solution!
7*11 = 77 (greater than 35) and 3*7 = 33 (lesser than 35)

*Note that 8 is also true but in question it is explicitly said that integer must be odd..

Question No 94

What is 3/4 of 92 plus 13?

Select the correct answer

85 81 83 82

Solution!
(3/4) * 92 = 69

69 + 13 = 82.

Question No 95

If A/B is 2/3 and difference between values of A and B is 10 What is value of B?

Select the correct answer

10 20 30 60

Solution!
If B is 30, A is 20 so difference of 10 is maintained..

Question No 96

A bus covers a distance of 60 Km in 1.5 hr. How far it would travel in half hour.

Select the correct answer

10 20 30 40

Solution!
Distance covered in 1.5 hr = 60

Distance covered in 1 hr = 60/1.5 = 40 Km

Distance Covered in 0.5 hr = 40 * 0.5 = 20.

Question No 97

Subtract eight and nine from twenty-five.

Select the correct answer

17 16 8 9

Solution!
25 - 8 - 9 = 8.

Question No 98

A cigarette case is full of cigars and cigarettes, probability of a cigarette is 8/15. What is the ratio of cigars to cigarettes.

Select the correct answer

8/7 7/15 7/8 8/15

Solution!
In 15 cigars and cigarettes there are 8 cigarettes So ratio between cigars and cigarettes is 8/7. Which means there are 8 cigarettes and 7 cigars..

Question No 99

What is average of 3, 5 and 10?

Select the correct answer

4 5 6 8

Solution!
(3+5+10)/3 = 18/3 = 6.

Question No 100

What is 55% of 320?

Select the correct answer

146 176 156 144

Solution!
55 * (320 / 100) = 176

Quick way to find answer from options is

50% of 320 is 160 so answer should be greater than 160
Only one option is greater than 160 which is 176..