Japheth is 20 years older than his son. 2 years from now, his son will be
12 of his age while his child will be
25 of his son. Express his child’s present age as a fraction of Japheth's present age. Leave your answer in its simplest form.
| |
Japheth |
Japheth's son |
Japheth's child |
Difference between
Japheth and Japheth's son |
| Before |
10 u - 2 |
5 u - 2 |
2 u - 2 |
20 |
| Change |
+ 2 |
+ 2 |
+ 2 |
|
After
|
2x5 |
1x5 |
|
|
| |
5x1 |
2x1 |
|
Comparing Japheth, his son and his child
in the end |
10 u |
5 u |
2 u |
5 u |
The repeated identity is the age of Japheth's son. LCM of 1 and 5 is 5.
The difference in age between Japheth and Japheth's son remains unchanged.
Difference in age between Japheth and Japheth's son
= 10 u - 5 u
= 5 u
5 u = 20
1 u = 20 ÷ 5 = 4
His child's present age
= 2 u - 2
= 2 x 4 - 2
= 8 - 2
= 6
Japheth's present age
= 10 u - 2
= 10 x 4 - 2
= 40 - 2
= 38
His child's present age as a fraction of Japheth's present age
=
638=
319 Answer(s):
319 
