word problem

Question

A recipe for peanut butter requires 12 pounds of butter and 10 pounds of peanuts. A pound of peanuts costs four times as much as a pound of butter. If the total cost of the batch of peanut butter is $91, how much does one pound of butter cost?

Answer 1

Let b equal the cost of a pound of butter. The cost of a pound of peanuts is then 4b (four times as much).

 

The total cost is the price per pound times the number of pounds for each ingredient, added together. This must equal 91.

 

This leads to an equation:

 

12b + 10(4b) = 91.

 

Solve it:

 

12b + 40b = 91

52b = 91

b = 91/52 = 1.75

 

The butter costs $1.75 per pound.