water is pumped into a tank at a rate of r(t) and is draining from the tank at a rate of d(t), each in…

water is pumped into a tank at a rate of r(t) and is draining from the tank at a rate of d(t), each in gallons per minute. which expression represents the rate at which the amount of water in the tank is changing? d(t) - r(t) d(t) - r(t) r(t) - d(t) r(t) - d(t)
Answer
Explanation:
Step1: Understand the rates
The rate of water being pumped in is $R(t)$ and the rate of water draining is $D(t)$.
Step2: Determine the net - rate
The rate of change of the amount of water in the tank is the inflow rate minus the outflow rate.
Answer:
$R(t)-D(t)$