Question

Robin can clean 72 rooms in 6 daysHow many rooms can Robin clean in 9 days?A. 64B.108C. 648 D. 9

Answer 1

72 rooms are proportional to 6 days. To find how many rooms are proportional to 9 days, we can use the next proportion:

$\frac{72\text{ rooms}}{x\text{ rooms}}=\frac{6\text{ days}}{9\text{ days}}$

Solving for x,

$\begin{gathered} 72\cdot9=6\cdot x \\ \frac{648}{6}=x \\ 108\text{ rooms=x} \end{gathered}$

Robin can clean 108 rooms in 9 days