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Q:

A train speeds past a pole in 15 seconds and a platform 100 m long in 25 seconds. Its length is:

A) 50 m	B) 150 m
C) 200 m	D) data inadequate

Answer & Explanation Answer: B) 150 m

Explanation:

Let the length of the train be x metres and its speed be y m/sec.
Then, (x/y)= 15 $\Rightarrow$ y =(x/15)

(x+100)/25 = x/15

=> 15(x + 100) = 25x

=> 15x + 1500 = 25x

=> 1500 = 10x

=> x = 150 m.

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Filed Under: Problems on Trains

Q:

If two times of the daughter’s age in years is included to the mother’s age, the total is 70 and if two times of the mother’s age is included to the daughter’s age, the total is 95. So the Mother’s age is,

A) 30	B) 38
C) 40	D) 41

Answer & Explanation Answer: C) 40

Explanation:

Let daughter’s age = A and mother’s age = B
Given: 2A+B = 70 and A+2B = 95
Solving B, we will get B = 40.

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Filed Under: Problems on Ages

Q:

If Raj was one-third as old as Rahim 5 years back and Raj is 17 years old now, How old is Rahim now?

A) 40	B) 41
C) 36	D) 48

Answer & Explanation Answer: B) 41

Explanation:

Raj’s age today = 17 decades,
Hence, 5 decades back, he must be 12 years old.
Rahim must be 36 years old, Because (3×12).
5 years back Rahim must be 41 years old today. Because (36+5).

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Filed Under: Problems on Ages

Q:

A man’s current age is $\frac{2}{5}$ of the age of his father. After 8 years, he will be $\frac{1}{2}$ of the age of his father. What is the age of father at now ?

A) 50	B) 40
C) 33	D) 30

Answer & Explanation Answer: B) 40

Explanation:

Let, father’s current age is A years.
Then, Man’s current age = $[(\frac{2}{5} * A)]$ years.

$[(\frac{2}{5} * A)]$ +8= $(\frac{1}{2}) (A + 8)$

2(2A+40) = 5(A+8)

A = 40

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Filed Under: Problems on Ages

Q:

The ages of Krish and Vaibhav are in the proportion of 3 : 5. After 9 years, the proportion of their ages will be 3 : 4. Then the current age of Vaibhav is:

A) 10	B) 13
C) 15	D) 18

Answer & Explanation Answer: C) 15

Explanation:

Krish’s age = 3A and Vaibhav’s age = 5A

(3A+9)/(5A+9) = 3/4

=> 4 (3A + 9) = 3 (5A + 9)

=> A = 3

Therefore, Vaibhav’s age = 15 years.

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Filed Under: Problems on Ages

Q:

The ages of X and Y are in the proportion of 6:5 and total of their ages is 44 years. The proportion of their ages after 8 years will be

A) 3:6	B) 6:3
C) 8:7	D) 9:5

Answer & Explanation Answer: C) 8:7

Explanation:

Let current ages of X and Y correspondingly, is 6A & 5A
Given: 6A + 5A = 44
=> A = 4
Proportion of ages after 0.8 decades will be
6A + 8 : 5A + 8 $\Leftrightarrow$ 32:28 (or) 8:7

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Filed Under: Problems on Ages

Q:

The age of a person is thrice the total ages of his 2 daughters. 0.5 decades hence, his age will be twice of the total ages of his daughters. Then what is the father’s current age? [0.5 Decades = 5 Years]

A) 35 years	B) 40 years
C) 45 years	D) 47 years

Answer & Explanation Answer: C) 45 years

Explanation:

Let, Total of current ages of the 2 daughters is A years.
Then, father’s current age = 3A years.
(3A + 5) = 2 (A +10)
3A + 5 = 2A + 20
A = 15
Therefore, father’s current age = 45 years.

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Filed Under: Problems on Ages

Q:

If 47. 2506 = 4*A + 7/B + 2*C + 5/D + 6*E, then the value of 5*A + 3*B + 6*C + D + 3*E is :

A) 55.6003	B) 53.603
C) 153.6003	D) 213.003

Answer & Explanation Answer: C) 153.6003

Explanation:

4*A + 7/B + 2*C + 5/D + 6*E =47.2506
=> 4 * A + 7/B + 2 *C + 5/D + 6*E = 40 + 7 + 0.2 + 0.05 + 0.0006
Comparing the terms on both sides, we get :
4*A =40, 7/B = 7, 2*C = 0.2, 5/D = 0.05, 6*E = 0.0006
A = 10,
B = 1,
C = 0.1,
D = 100,
E = 0.0001.
5*A + 3*B + 6*C + D + 3*E =(5*10) + (3*1) + (6*0.1) +100 +(3*0.0001)
=50 + 3 + 0.6 + 100 + 0.003 = 153.6003.

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Filed Under: Decimal Fractions

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