It takes 0.5

gallon of cream to make 1
pound of butter.

CLEAR CHECK
How much butter could you make with 0.25
gallons of cream?
pound
How much cream would you need to make 2.5
pounds of butter?
gallons

With 0.25 gallons of cream, you could make 0.5 (1/2) pound of butter.

To make 2.5 pounds of butter, you would need 1.25 gallons of cream.

1 gallon of cream makes 2 pounds of butter, so to make 2.5 pounds of butter, you would need 1.25 gallons of cream.