The ratio of two brothers John and Harry is 4 / 5. However if the age of John before 10 years and that of Harry after 10 years then the original ratio is reversed. What is the age of John?

John age is = a and harry= b

given that a /b = 5 / 4

4a= 5 b

4a - 5b= 0.... Equation 1

and also given that a - 10 / b + 10 = 4 / 5

5 a- 50 = 4 b + 40

5a - 4 b = 90.... Equation 2

by solving both equation

a = 50

.
In following questions, one term in number series is incorrect.

Find out the incorrect number

6, 14, 30, 64, 126

Find out the incorrect number

6, 14, 30, 64, 126

Each term is multiplied by 2 and then increased by 2 to obtain the next term.

So, 64 is wrong and must be replaced by (30 * 2 + 2) i.e. 62..

In following questions, a sequence of groups of alphabets and numbers is provided with one term missing , Choose the missing term from options. C4X, F9U, 116R, ?

The first letter of each term is moved three steps forward and the last letter is moved three steps backward to obtain the corresponding letters of the next term.

.
Pointing to a man in photograph, a woman said, His brother father in the only son of my grandfather. How is the woman related to the man in the photograph?

Blood relation analysis.

Only son of women grandfather= woman father

Man's brother father =man father

so woman is man's sister

.
These are six persons A ,B, C, D , E,and F is a sister of F. B is a brother of E's husband. D is the father of A and grandfather of F. There are two fathers, three brothers and a mother in the group. Who is the mother?

D is father of A and grandfather of F. So, A is father of F. Thus, D and A are the two fathers. C is the sister of F. So, C is the daughter of A . Since there is only one mother, it is evident that E is the wife of A and hence the mother of C and C and F. So, B is brother of A . There are three brothers. So, F is the brother of C. Clearly, E is the mother..

The sum of age 5 children born at the interval of 2 year each is 40 year. Find out the age of eldest child?

let's age of youngest child = x

Then the age of 5 children can be written as x,( x + 2) ,(X + 4 ),(x + 6) and( X + 8).

Age of elders child = X + 8

Then ,

X + (X + 2 )+ (X+ 4) +( X + 6) + (X + 8) = 40

5 X + 20 = 40

5 X = 40 - 20

X = 20 / 5

X = 4

Age of elders child = X + 8

4 + 8 = 12.

.
The difference of the squares of two consecutive odd integers is divisible by which of the following integers ?

Let the two consecutive odd integers be (2n + 1) and (2n + 3). Then,

(2n + 3)2 - (2n + 1)2 = (2n + 3 + 2n + 1) (2n + 3 - 2n - 1)

= (4n + 4) x 2

= 8(n + 1), which is divisible by 8.

.
In following questions, a sequence of groups of alphabets and numbers is provided with one term missing , Choose the missing term from options. MHZ, NIW, OKT, PNQ, ?

The first letters of the terms are consecutive letters. The third letter of each term is moved three steps backward to obtain the third letter of the successive term. The middle letters of the first, second, third and fourth terms are moved one, two, three and four steps forward respectively to obtain the middle letter of the successive terms.

.