1) Three years ago, the ratio of the ages of A and B is 3:4 and the average of the ages of B and C after 4 years is 40 years. If after 9 years, A’s age is equal to the average ages of B and C, then what is the present age of C?

A.28 years

B.33 years

C.37 years

D.43 years

E.48 years

2) The average age of A, B, C and D is 42 years and the average ages of B, C and D is 28 years. If the sum of the ages of A and B is 144 years and after 10 years, the ratio of the ages of B to C is 7:3, then what is the present age of D?

A.8 years

B.7 years

C.12 years

D.5 years

E.None of these

3) Five years ago, the ratio of the ages of A to B is 2:1 and the present age of A is 20 years more than B. If C’s age is 20% more than the sum of the present age of A and B together, then what is C’s age after 8 years?

A.90 years

B.88 years

C.94 years

D.86 years

E.None of these

4) The respective ratio of the present ages of father to son is 7:3. Five years ago, the ratio of their ages was 5:2. Then what will be the son’s age, 10 years from now?

A.45 years

B.55 years

C.60 years

D.35 years

E.40 years

5) A’s age is 120% of B’s age and B’s age is 125% of C’s age. If the average of the ages of A, B and C is 50 years, the find 175% of C’s age?

A.70

B.80

C.60

D.50

E.None of these

Answers :

1) Answer: C

(A – 3)/(B – 3)=3:4

4A – 12=3B – 9

4A – 3B=3

((B + 4) + (C + 4))/2=40

B + C=72

A’s age after 9 years=72/2=36 years

A’s present age=36 – 9=27 years

4 * 27 – 3B=3

B=35 years

C=72 – 35=37 years

2) Answer: E

A + B + C + D=42 * 4=168

B + C + D=28 * 3=84

A + B=144

A=168 – 84 = 84 years

B =144 – 84 = 60 years

C + D =168 – (84 + 60) = 24 years

After 10 years B’s age=60 + 10=70 years

C’s age after 10 years=70 * 3/70=30 years

Present age of C=30 – 10=20 years

D =24 – 20 = 4 years.

3) Answer: E

(A – 5)/(B – 5) = 2/1

A – 5 = 2B – 10

A – 2B = -5

A = B + 20

B + 20 – 2B=-5

B = 25

A = 25 + 20=45

C = 120/100 * (45 + 25)

= 84 years

After 8 years C’s age = 84 + 8=92 years

4) Answer: B

The respective ratio of the present ages of father to son is 7:3

Father’s age = 7x

Son’s age = 3x

Five years age, Father’s age = 7x-5

Son’s age = 3x-5

(7x – 5)/(3x – 5) = 5/2

14x – 10 = 15x – 25

x = 15

Son’s present age = 15 * 3=45 years

After 10years, the son’s age = 55 years

5) Answer: A

A=120B/100

A=6/5 * B

B=125/100 * C

B=5/4 * C

5A/6=5/4 * C

A/3=C/2

A=3C/2

3C/2 + 5/4 * C + C=50 * 3

6C + 5C + 4C=600

C=40 years

175% of C’s age=175/100 * 40

=70