A Boat Can Go $45 \mathrm{mph}$ In Still Water $3 \mathrm{mph}$ B) $1 \mathrm{mph}$

Multiple Choice

A boat can go $45 \mathrm{mph}$ in still water. It takes as long to go 60 miles upstream as it does to go downstream 90 miles. How fast is the current?

A) $3 \mathrm{mph}$
B) $1 \mathrm{mph}$
C) $8 \mathrm{mph}$
D) $9 \mathrm{mph}$