Answer:
5.625 inches
Step-by-step explanation:
Given that:
Total Rainfall in inches (P) = 8 inches
The runoff volume (in inches) Q = ???
The curve number CN = 80
Recall that: The runoff volume can be calculated by using the formula:
for P > 0.2S
Q = 0 for P < 0.2S

where:
curve number CN = 80

S = 2.5 inches
Since the rainfall (P) is greater than 0.25
Then:




Q = 5.625 inches
Thus, the runoff volume = 5.625 inches
71/20 or 3.55 as a decimal
Assuming its the same temp, use this equation for pounds and minutes then solve:

cross multiply
50(3.5) = 175 minutes
it'll take an 2 hours 55 minutes