Solve the Problem $4 \mathrm{hr}$ B) $5 \mathrm{hr}$ C) $6 \mathrm{hr}$ D) $1 \mathrm{hr}$

Multiple Choice

Solve the problem.
-From a point on a river, two boats are driven in opposite directions, one at 9 miles per hour and the other at 6 miles per hour. In how many hours will they be 60 miles apart?

A) $4 \mathrm{hr}$
B) $5 \mathrm{hr}$
C) $6 \mathrm{hr}$
D) $1 \mathrm{hr}$