Question

A father gives $1\%$ of his monthly income to his two sons as pocket money. The elder son gets $20\%$ of the total amount of money given out he spends $20\%$ of his share. If he saves Rs. $20$ per month, determine father's monthly income.

Answer 1

Let monthly income be x

Total money given out = $\frac{x}{100}$

elder son gets = $\frac{20}{100}\times \frac{x}{100}=\frac{x}{500}$

elder son spends - 20%

elder son saves - 80%

$\Rightarrow \frac{80}{100}\times \frac{x}{500}=\frac{8}{5\times 125}=20$

$x\Rightarrow 12,500$