A man spends 35\% of his income on food, 25\% on children's education and 80\% of the remaining on house rent. What percent of his income he is left with?
(a)8\%
(b)10\%
(c)12\%
(d)14\%
Answer
Answer (as printed): A
Explanation
Let the total income be $x$. Then, income left $=(100-80) \%$ of $[100-(35+25)] \%$ of $x=20 \%$ of 40\% of $x$. $$=\left(\frac{20}{100} \times \frac{40}{100} \times 100\right) \% \text { of } x=8 \% \text { of } x .$$
Explanation as extracted from the printed page; notation may be imperfect.