Question

A grading machine can grade 48 tests in 1 minute. How

long will it take the machine to grade 300 tests?

Answer 1

`\bf \begin{array}{ccll} tests&minutes\\ \text{\textemdash\textemdash\textemdash}&\text{\textemdash\textemdash\textemdash}\\ 48&1\\ 300&m \end{array}\implies \cfrac{48}{300}=\cfrac{1}{m}\implies m=\cfrac{300\cdot 1}{48}`