50.6k views
25 votes
Solve using a proportion.

Blake earns $60 a week mowing lawns. He
saves 30% of what he makes per week and
spends the rest on food. How much does
Blake spend each week on food?
word

User Nogood
by
4.2k points

2 Answers

8 votes

well, we know that he makes $60 weekly, that'd be the 100%, we also know that he saves 30% of that and the rest, well, 100% - 30% = 70%, so 70% he spends it on food.

if we take 60 to be the 100%, what is 70% of it?


\begin{array}{ccll} amount&\%\\ \cline{1-2} 60 & 100\\ x& 70 \end{array} \implies \cfrac{60}{x}=\cfrac{100}{70}\implies \cfrac{60}{x}=\cfrac{10}{7} \\\\\\ 420=10x\implies \cfrac{420}{10}=x\implies 42=x

User Mahdad
by
3.8k points
3 votes
Blake will end up spending $20 a week on food
User Dennis Klopfer
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3.5k points