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?
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 5 of 6.
Nagarjuna.N said:
1 decade ago
Let Mother Present age = x
Person age = (2/5)x
After 8 Years Persons Age Will be = (2/5)x + 8
After 8 Years Mother Age Will Be x + 8
Given That After 8 years, Person will be one-half of the age of his mother.
Here One-Half Means 3/2 actually . (But He Take 1/2 in the Explanation . So let we take 1/2).
(2/5)x + 8 = (1/2)(x+8).
(2x + 40)/5 = (x+8)/2.
4x + 80 = 5x + 40.
x = 40.
Mother Present Age x = 40.
Person age = (2/5)x
After 8 Years Persons Age Will be = (2/5)x + 8
After 8 Years Mother Age Will Be x + 8
Given That After 8 years, Person will be one-half of the age of his mother.
Here One-Half Means 3/2 actually . (But He Take 1/2 in the Explanation . So let we take 1/2).
(2/5)x + 8 = (1/2)(x+8).
(2x + 40)/5 = (x+8)/2.
4x + 80 = 5x + 40.
x = 40.
Mother Present Age x = 40.
Cynthia said:
1 decade ago
Please I need explanation on solving this equation:
2/5x+8 = 1/2(x+8).
Are we not meant to cross multiply. I don't understand how you came about the 40?
2/5x+8 = 1/2(x+8).
Are we not meant to cross multiply. I don't understand how you came about the 40?
Leena said:
1 decade ago
Can anybody explain me?
(2x+40)/5 = (x+8)/2.
4x + 80 = 5x + 40.
(2x+40)/5 = (x+8)/2.
4x + 80 = 5x + 40.
Uzma said:
1 decade ago
2x/5+8/1 = 1/2(x+8).
(here we are going to cross multiply 5*8 = 40).
2x = 40/5 = 1/2(x+8).
2x = 40/5 = 1/2(x+8).
4x+80 = 5x+40.
Then x = 80-40.
= 40.
Hope you got it.
(here we are going to cross multiply 5*8 = 40).
2x = 40/5 = 1/2(x+8).
2x = 40/5 = 1/2(x+8).
4x+80 = 5x+40.
Then x = 80-40.
= 40.
Hope you got it.
Shivani said:
1 decade ago
In question they have asked present age of mother, But 40 is after 8 years old. Shouldn't it be 40-8-32?
Vijitha said:
1 decade ago
Can any one explain me - one half means 3/2 or 1/2 - if exactly one-half means 3/2 means- why they taken it as 1/2 while solving - please explain me about the difference of both?
Kiran said:
1 decade ago
Second step how wrote by first line?
Sumit said:
1 decade ago
Person mother.
2 5.
1 2 (8 year hence).
Then mother's present age is.
M = (5*8*1)/(5*1) - (2*2).
M = 40.
2 5.
1 2 (8 year hence).
Then mother's present age is.
M = (5*8*1)/(5*1) - (2*2).
M = 40.
Aparna mohan said:
1 decade ago
How 59(x+8) came?
Akshitha said:
1 decade ago
ONE HALF is the irreducible fraction resulting from dividing one by two (½), or any number by its double; multiplication by one half is equivalent to division by two. It appears often in mathematical equations, recipes, measurements, etc. Half can also be said to be one part of something divided into two equal parts.
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