Question

A pool initially contains 1,385 cubic feet of water. Apump begins emptying the water at a constant rate of20 cubic feet per minute. Which of the followingfunctions best approximates the volume v(t), incubic feet, of water in the pool t minutes afterpumping begins, for 0 st s 69 ?A) y(t) = 1,385 - 200B) v(t) = 1,385 – 69tC) v(t) = 1,385 + 20tD) v(t) = 1,385 +691

Answer 1

Since the tank has an initial volume we can initiate the equation like this

$V(t)=1385$

then since the pool is emptying, it means that the volume is decreasing

$V(t)=1385-$

then the rate at which it is decreasing is 20 cubic feet per minute, meaning that the final equation should be

$V(t)=1385-20t$