For efficiency the top one is 50% and the bottom one is 72%
A)
R1 = 30/(7*60)
We are multiplying 7 with 60 because there are 60 seconds in 1 minute.
R1 = 30/420 = 0.0714 gallons/second
b) For this we need to express gallons to cubic meters.
1 gallon = 0.003785 m^3
R2 = 0.0714*0.003785 = 0.00027 m^3/s
c) V = R2*t where V is volume of some tank.
which means that
t=V/R2
t = 3698.8s or
t = 1.0274 hours