Question

A civil servant spent 2/7 of his monthly salary on clothes, 7/20 of the remainder on feeding and save the rest. If he spent N7,000 on feeding. Find his monthly salary ​

Answer 1

`\stackrel{ \textit{on clothes} }{\cfrac{1}{7}x+\cfrac{1}{7}x}~~ + ~~\stackrel{ \textit{on feeding} }{\cfrac{1}{7}x+\cfrac{1}{7}x+\cfrac{1}{7}x+\cfrac{1}{7}x+\cfrac{1}{7}x}\implies \text{\LARGE 1x}whole`

so we know that 7/20 of that remainder is N7000 bucks, so

`\stackrel{ \textit{remainder, on feeding} }{\cfrac{x}{7}+\cfrac{x}{7}+\cfrac{x}{7}+\cfrac{x}{7}+\cfrac{x}{7}}\implies \cfrac{5x}{7}\hspace{5em}\left( \cfrac{5x}{7} \right)\left( \cfrac{7}{20} \right)~~ = ~~7000 \\\\\\ \left( \cfrac{5x}{20} \right)\left( \cfrac{7}{7} \right)=7000\implies \cfrac{5x}{20}=7000\implies 5x=140000 \\\\\\ x=\cfrac{140000}{5}\implies x=28000`