Q.1 Ratio of the ages of the father & the son at present is 6:1. After 5 years ratio will become 7:2. What is the present age of the son ?

A) 30 yrs

B) 31 yrs

C) 32 yrs

D) 33 yrs

Ans. A

Sons’s age = Y * T(a-b) / difference of cross product

Or  1 * 5 (6-1) / 12 – 7

5*5 / 5 = 5 yrs

Father’s age = X *T (a-b) / Difference of cross product

6*5 (6-1) / 12-7

=6*5 = 30 yrs

Q.2 10 yrs back sum of the ages of a mother & her daughter is 45. If the ratio of their present ages be 9:4. Then the present age of the daughter is :-

A) 20 yrs

B) 21 yrs

C) 22 yrs

D) 23 yrs

Ans. A

10 yrs back, D + M = 45

Now, at present, D + M =45+10 = 55

Thus, 9x+4x=55

13x=55    

Or x=5

Or D=4x = 20

Q.3 Suresh’s father is 2yrs older than his mother. His age is 3yrs less than half of his mother ago. He was born when his father was 23yrs old. Find the age of Suresh ?

A) 14yrs

B) 15yrs

C) 16yrs

D) 17 yrs

Ans. A

F = 2 + M

M = F – 2

Or S = M/2 – 3

F-2/2 – 3

Or F-8/2

Or F = S+23

= 23 + F-8/2

Or F = 37+F / 2

F = 37

Now, Suresh’s age = 37-23 = 14 yrs

Q.4 Three years earlier father was 7 times as old as his son. Three years hence, father’s age would be four times that of his son. What is the present age of son ?

A) 9 yrs

B) 10 yrs

C) 11 yrs

D) 12 yrs

Ans. A

Shortcut:

T2(z-1) + T1(x-1)

3(4-1)+3(7-1) / 7-4

= 9yrs

Q.5 Peter is twice as old as Paul was when Peter was as old as Paul is now. The combined age of Peter and Paul is 42years. How old is peter now?

A) 21

B) 28

C) 24

D) 26

Ans. B

peter’s age = x

paul’s age = y

x+y =42

Since, x=2y, then

x+2y=42

3y = 42

y=14 i.e. Paul’s age

Or Peter’s age = 28 years