# Mental Arithmetic

#### Question No 1

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?

Solution!
Shadow of 40m pole = 30m

Shadow of 1m pole = 30/40m

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

#### Question No 2

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

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

#### Question No 3

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

Solution!
19+17+15 = 51.

#### Question No 4

What is the sum of first 5 positive even integers?

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

#### Question No 5

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

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

#### Question No 6

Divide 52 by 4 and add 17 multiplied by 3.

Solution!
52 / 4 = 13

17 * 3 = 51

13 + 51 = 64.

#### Question No 7

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?

Solution!
x/15 = 10/3

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

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

#### Question No 8

100/101 = ?

Solution!
100/101 = 0.990099.

#### Question No 9

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?

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 10

Multiply 72 by 15.

Solution!
72 * 15 = 1080

Other way is

72 * 10 = 720
and
720 / 2 = 360

720 + 360 = 1080.

#### Question No 11

What is 3206 divided by 7?

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 12

Multiply 694 by 11.

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 13

Deduct 7.3 from 34.2.

Solution!
34.2 - 7.3 = 26.9.

#### Question No 14

What is 55% of 320?

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..

#### Question No 15

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

Solution!
572 is completely divisible by 6..

#### 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.

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

Subtract 369 from 1250.

Solution!
1250 - 369 = 881.

#### Question No 18

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

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 19

Which of the following is a prime number?

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 20

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

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

#### Question No 21

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

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

#### Question No 22

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

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

42+x = 55

x = 55-42
=13.

#### Question No 23

Divide 672 by 12.

Solution!
672 / 12 = 56.

#### Question No 24

What is 9 multiplied by 8?

Solution!
9 * 8 = 72.

#### Question No 25

What is average of 12 , 15 and 18?

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

#### Question No 26

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

Solution!
No answer description available for this question..

#### Question No 27

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

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

#### Question No 28

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

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

#### Question No 29

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?

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 30

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

Solution!
No answer description available for this question..

#### Question No 31

Deduct 865 from 1063.

Solution!
1063 - 865 = 198.

#### Question No 32

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

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

378 * ? = 252

Solution!
252 / 378 = 2/3.

#### Question No 34

What is 3/4 of 92 plus 13?

Solution!
(3/4) * 92 = 69

69 + 13 = 82.

Solution!
1.99 * 3 = $5.97. #### Question No 73 What is 15 multiplied by 11? #### Select the correct answer Solution! 15 * 11 = 165. #### Question No 74 What is 45% of 300? #### Select the correct answer 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 75 What is 126 divided by 3? #### Select the correct answer Solution! 126 / 3 = 42. #### Question No 76 A bus covers a distance of 60 Km in 1.5 hr. How far it would travel in half hour. #### Select the correct answer 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 77 A/B = 2/3. If value of A is 8 What is the value of B? #### Select the correct answer 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 78 How much is 25% of$200?

Solution!
25 * (200/100) = $50 Or 200 / 4 =$50.

#### Question No 79

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

Solution!
(2/5) * 90 = 36

(5/6) * 78 = 65

36 + 65 = 101.

#### Question No 80

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

Solution!
No answer description available for this question..

#### Question No 81

Multiply 7 by 12 and divide by 6.

Solution!
7 * 12 = 84

84 / 6 = 14.

#### Question No 82

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

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

#### Question No 83

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

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

#### Question No 84

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?

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 85

Subtract eight and nine from twenty-five.

Solution!
25 - 8 - 9 = 8.

#### Question No 86

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

Solution!
86 * 9 = 774

13 * 6 = 78

774 + 78 = 852.

#### Question No 87

7/21 in lowest term is?

Solution!
7/21 = 1/3.

#### Question No 88

Divide 56 by 8 and add 17.

Solution!
56 / 8 = 7

7 + 17 = 24.

#### Question No 89

2+2*2?

Solution!
2 + (2 * 2) = 6

Multiplication is performed first and subtraction afterwards.

Sequence of solving operators is
/
*
+
-.

#### Question No 90

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

Solution!
100 - 64 = 36%.

#### Question No 91

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

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

#### Question No 92

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

Solution!
(5/8) * 112 = 70

and
(7/8) * 88 = 77

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

#### Question No 93

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

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

#### Question No 94

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

Solution!
Let sum is x.

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

#### Question No 95

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

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

#### Question No 96

2664/12/6=?

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

#### Question No 97

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

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

#### Question No 98

What is 5/8 of 240?

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

#### Question No 99

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

Solution!
6+5+4 = 15.

#### Question No 100

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

Solution!
x/4 = 24
x = 24*4
x = 96.
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## Tips to Solve Mental Arithmetic Test

Mental arithmetic is an awesome brain-storming math IQ test that is done without a calculator. It is to check the sharpness of mind and how quickly a student or even an interviewing candidate can solve the arithmetic problems. Most candidates and students opt for mental math classes to practice solving Math problems in the mind and not using the pen or paper. The mental arithmetic involves four types of calculations generally like addition, subtraction, division, and multiplication. Its main aim is to improve cognitive ability and help brain function faster.

This maths IQ test helps you to simplify the calculations and get the answers quickly. Like, if we have to add two numbers like 91 and 45 then use the simplified steps. Firstly, add the second numbers of both the digits like 1 + 5= 6 and then add the first numbers of these digits like 9+4 = 13 so the total answer is 136 where you need to place answers of second numbers on the second place and the answer of first numbers on the first place. This way you can solve the subtraction problems too.

While, in multiplication problems, you have to place zero at the end of two-digit numbers like 3X75, so it goes like 3x70 and 3x5 so the answer is 210+15= 225. This way you will get the exact answers. There are varied rules for square roots, divisions, etc. Here you can learn by practicing the various significant rules of the Mental arithmetic. It will help you to solve tedious questions too.