Question

A store is having a sale on walnuts and chocolate chips. For 5 pounds of walnuts and 3 pounds of chocolate chips, the total cost is $17 . For 2 pounds of walnuts and 12 pounds of chocolate chips, the total cost is $23 . Find the cost for each pound of walnuts and each pound of chocolate chips.

Answer 1

Let's w is pound of walnuts and c is pound of chocolate chips
       5w + 3c = 17
        2w + 12c = 23    --> w = -2 + 12c
 5w + 3c = 17
 5 (-2) + 12c + 3c = 17
    -10      + 15c     = 17
                15c        = 17 + 10
                  15c       = 27
                       c       = 1.8 ( cost for each pound of chocolate chip )

5w + 3c = 17
5w  + 3 (1.8) = 17
5w   +    5.4    = 17
          5w          = 17 - 5.4 
           5w          = 11.6 
              w          = 2.32 ( cost for each pound of walnut )
Hope it useful.