Question 1203910
w, walnut price
c, chocolate chips price


{{{system(7w+9c=37,5w+3c=17)}}}


Three times equation #2.
{{{system(7w+9c=37,15w+9c=51)}}}


Now do E2-E1.
{{{8w=14}}}
{{{4w=7}}}

{{{w=7/4}}}

{{{highlight(w=1.75)}}}, and you can find the value for c.