JAMB - Mathematics (2009 - No. 5)
A student spent 1/5 of his allowance on books, 1/2 of remainder on food and kept the rest for contingencies. What fraction was kept?
7/15
8/15
2/5
4/5
설명
Let his allowance = y.
\(Books = \frac{y}{5}\)
\(Remainder: y - \frac{y}{5} = \frac{4y}{5}\)
\(Food: \frac{1}{2} \times \frac{4y}{5} = \frac{2y}{5}\)
\(Contingencies: \frac{4y}{5} - \frac{2y}{5} = \frac{2y}{5}\)
Therefore, he kept \(\frac{2}{5}\) of his allowance for contingencies.