Aptitude - Problems on Ages - Discussion

Discussion Forum : Problems on Ages - General Questions (Q.No. 13)
13.
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?
32 years
36 years
40 years
48 years
Answer: Option
Explanation:

Let the mother's present age be x years.

Then, the person's present age = 2 x years.
5

2 x + 8 = 1 (x + 8)
5 2

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

x = 40.

Discussion:
59 comments Page 1 of 6.

Prachi said:   1 decade ago
One-half means 3/2 na?

Jaz said:   1 decade ago
One-half meaning is 1/2 only.

Aditya said:   1 decade ago
Hey can any one explain properly?

Yuga J. said:   1 decade ago
@Aditya Ive solved it this way....

The ratio of the person's and his mother's present age is 2:5.
Therefore, take the person's age as 2x and his mother's age as 5x.

After 8 years[(add 8 to both values)...i.e. (2x+8) and (5x+8)] their age ratio is 1:2.


Hence,
(2x+8)/(5x+8)=1/2
4x+16=5x+8
x=8

So, the mother's age=5*8=40
(10)

Bharathi.m said:   1 decade ago
Thanks yuga.

Mithu Sen said:   1 decade ago
Hey Yuga.

Thanks your way of explaination was very simple.

Mrs pallavi said:   1 decade ago
Let the person age x, mother age y.

x=2/5*y............condn(1)
(x+8)=1/2(y+8).....condn(2)

from 1
5x-2y=0.........(a)

from 2
2x-y=-8 ..........(b)

from a & b
we get x=16 & y=40

Answer is 40.

Subru said:   1 decade ago
x=mother's age
sons age=2/5*x
x=40(answer)
sons age=100
how this possible

Ajith said:   1 decade ago
Good yuga! simplified!

Deepa said:   1 decade ago
Gr8 Yuga!

Can somebody explain the Actual calculation presented by them?


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