Solve the Problem $r$ Is Given By $V _ { W } = 20 t$

Solve the problem.
-The volume of water added to a circular drum of radius $r$ is given by $V _ { W } = 20 t$ , where $V _ { W }$ is volume in $\mathrm { cu } \mathrm {} \mathrm { ft }$ and $\mathrm { t }$ is time in sec. Find the depth of water in a drum of radius $4 \mathrm { ft }$ after adding water for $10 \mathrm { sec }$ . (Round result to one decimal place.)

A) $12.6 \mathrm { ft }$
B) $4.0 \mathrm { ft }$
C) $8.0 \mathrm { ft }$
D) $2.0 \mathrm { ft }$