Question

A chef made 30 donuts in 60 minutes. How long would it take him to
make 90 donuts?

Answer 1

Answer: 180 minutes

Explanation:

Cross multiply

90*60 = 5400

5400/30 = 180

Answer 2

`\bf \begin{array}{ccll} donuts&minutes\\ \cline{1-2} 30&60\\ 90&x \end{array}\implies \cfrac{30}{90}=\cfrac{60}{x}\implies \cfrac{1}{3}=\cfrac{60}{x}\implies x=180`