The present ages of three persons in proportions 4 : 7 : 9. Eight years ago, the sum of their ages was 56. Find their present ages [in years].
8, 20, 28
16, 28, 36
20, 35, 45
None of these
Explanation:
Let their present ages be 4$ x $, 7$ x $ and 9$ x $ years respectively.
Then, $\left(4x- 8\right)$ + $\left(7x - 8\right)$ + $\left(9x- 8\right)$ = 56
$\Rightarrow$ 20$ x $ = 80
$\Rightarrow x $ = 4.
$\therefore$ Their present ages are 4$ x $ = 16 years, 7$ x $ = 28 years and 9$ x $ = 36 years respectively.