I've got a word problem I'm having trouble with

Question

A biker mixed 11 pounds of raisins that cost $2.30 per pound with peanuts that cost $4.50 per pound to make a mixture that cost $3.29 per pound. How many pounds of peanuts did the biker use?

Answer 1

Let x = the weight of the peanuts that the biker added to the 11 pounds of raisins.  The weight of the final mixture of raisins and peanuts is 11 + x.

 

11*($2.30) + x*($4.50) = (11+x)*($3.29)

 

25.30 + 4.5x = 36.19 + 3.29x

 

Solve for x.