Answer:
B
11 dollars
Step-by-step explanation:
7x+13 is the sum of the two order
you know that one order is 3x+5, so if you subtract it from the total you get the other order
7x+13-(3x+5) =7x+13-3x-5 = 4x+8
if he spent 90 dollars in total then we can say that
7x+13 = 90
7x=77
x=11
11 dollars per box
Explanation: