Aptitude Problems On AgesPage 2
9. | | The ratio of the present ages of two brothers is 1:2 and 5 years back, the ratio was 1:3. What will be the ratio of their ages after 5 years? | | (a)3 : 5 | | (b)4 : 5 | | (c)5 : 3 | | (d)2 : 5 |
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Answer is: ALet the present ages of the two brothers be X years and 2X years respectively
Then, (X-5)/(2X-5) = 1/3
⇒ 3(X-5) = 2X-5
X =10
∴ Required ratio =(X+5) :(2X+5) = 15 : 25 = 3 : 5
10. | | Hitesh is 40 years old and Ronu is 60 years old. How many years ago was the ratio of their ages 3 : 5? | | (a)5 years | | (b)10 years | | (c)15 years | | (d)20 years |
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Answer is: BSuppose, the ratio was 3 : 5, X years ago.
Then, (40 - X)/(60 - X) = 3/5
⇒ 5(40 - X) = 3(60 - X)
⇒ 2X = 20
⇒ X = 10 years
11. | | The ratio of the father's age to his son's age is 7 : 3. The product of their ages is 756. The ratio of their ages after 6 years will be : | | (a)2 : 1 | | (b)1 : 2 | | (c)3 : 1 | | (d)1 : 3 |
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Answer is: ALet the present ages of the father and son be 7X and 3X years respectively.
Then, 7X x 3X = 756
⇒ 21 X² = 756
X² = 36
X = 6
∴ Required Ratio =(7X + 6) :(3X + 6) = 48 : 24 = 2 : 1
12. | | The present age of three persons are in proportions 4 : 7 : 9. Eight years ago, the sum of their ages was 56. Find their present ages. | | (a)16, 28, 35 | | (b)16, 28, 30 | | (c)15, 28, 35 | | (d)15, 27, 35 |
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Answer is: ALet the present ages be 4X, 7X and 9X respectively. Then,
(4X - 8) + (7X - 8) + (9X - 8) = 56
⇒ 20X = 80
⇒ X= 4
∴ Their present ages are 16 years, 28 years and 35 years respectively.
13. | | A is two years older than B who is twice as old as C. If the total of the ages of A, B and C be 27, then how old is B? | | (a)10 | | (b)15 | | (c)20 | | (d)25 |
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Answer is: ALet C's age be X years. Then, B's age = 2X years.
A's age = (2X + 2) years
∴(2X +2) + 2X + X = 27
⇒ 5X = 25
⇒ X = 5
Hence, B's age = 2X = 2 x 5 = 10 years
14. | | 18 years ago, a father was three times as old as his son. Now the father is only twice as old as his son. Then the sum of the present ages of the son and the father is: | | (a)105 years | | (b)108 years | | (c)110 years | | (d)112 years |
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Answer is: BLet, the present ages of the father and son be 2X and X years respectively
Then,(2X - 18) = 3(X - 18)
⇒ X = 36
∴ Required sum =(2X + X) = 3X = 108 years.
15. | | A person 's present age is two fifth of the age of his mother. After 8 years, he will be one half of the age of his mother. How old is the mother at present? | | (a)40 years | | (b)41 years | | (c)42 years | | (d)43 years |
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Answer is: ALet the mother's present age be X years. Then,
The person's present age =(2/5 X) years
∴(2/5X + 8) = 1/2(X +8)
⇒ 2(2X + 40) = 5(X+8)
⇒ X = 40
16. | | Q is as much younger than R as he is older than T. If the sum of the ages of R and T is 50 years, what is definitely the difference between R and Q's age? | | (a)10 years | | (b)15 years | | (c)18 years | | (d)None of these |
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Answer is: DR – Q = R - T
⇒ Q = T Also R + T = 50
⇒ R + Q = 50
So,(R - Q) cannot be determined.
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