Ben and Jerry’s sells 2 times more ice cream cones ($3) than shakes ($8). If last month’s sales totaled $8,400, how many of each were sold?

Question

i need help solving this problem

Answer 1

Two equations:

if c is number of cones, and s is number of shakes, then 3c+8s=8400

Since # of cones c = twice the number of shakes s, then c=2s.

Combining these will yield:

3(2s)+8s=8400

6s+8s=8400

14s=8400 -------> s=600 shakes

if c=2s, then c=2(600) = 1200 cones