SSC CHSL 6 Mar 2018 Shift 1 Paper

% husk in 20 kg mixture = 5%
⇒ Quantity of husk = $\frac{5}{100}\times 20=1$kg
Let $\mathit{x}$ kg of husk is added
According to ques,
⇒ $\mathit{x}+1=\frac{20}{100}\times \left(\mathit{x}+20\right)$
⇒ $5\mathit{x}+5=\mathit{x}+20$
⇒ $5\mathit{x}-\mathit{x}=20-5$
⇒ $4\mathit{x}=15$
⇒ $\mathit{x}=\frac{15}{4}=3.75$
∴ 3.75 kg of husk must be added to make the husk content 20% in the new mixture.