Answer: 16 hours
Step-by-step explanation
Step 1: Split 8 in half because we are using half the amount of pumps which is 4. Now we know the amount of pumps being used.
Step 2: Next we find the unit rate by dividing 32 and 8 to get 4
Step 3: Lastly we multiply 4x4 because 4 is the amount of pumps being used and the other 4 is the unit rate. Once we multiply we get 16 which is the answer: 16 hours