Lamont's buys 9 gallons of ice cream. he has 34 guests coming. if each guest eats 2 1/2 cups, how many pints will he have left?

We know that 1 gallon is equal to 16 cups.
So 9 gallons is 144 cups.
each guest eats 2.5 cups, and there are 34 guests,
2.5 times 34 = 85, the amount eaten by the guests.
So to figure out whats left, subtract the eaten from the total.
144-85=59
59 is the answer. 
hope it helped :)