We have volume of gasoline = 14.0 gallon
Time taken to fill automobile tank = 1.50 minutes
So volume rate = 14.0 gallon/1.50 minutes = 9.33 gallon/ minute
We have density of gasoline = 0.77 kg/L = 6.073 lb/US gal
Mass rate = Density * Volume rate
= 9.33 gallon/ minute*6.073 lb/US gal = 56.68 lb/min
So mass flow rate delivered by the gasoline pump in lbm/min = 56.68