Question

A father gives 1% of his monthly income to his two sons as pocket money. The elder son gets 80% of the total amount of money given and he spends 80% of his share. If he saves ₹ 20 per month, determine father's monthly income.​

Answer 1

let father's income be ₹ x then

$\frac{80}{100} of \: 1\% \: of \: father's \: income \: is \: ₹100 \\ \frac{80}{100} \times \frac{1}{100} \times x = 100 \\ x = \frac{100 \times 100 \times 100}{80} \\ x = \frac{100000}{8} \\ x = ₹12500$

Therefore, Father's income is ₹12,500