Respuesta :

texaschic101
c + 5t = 70
t = c - 4

c + 5(c - 4) = 70
c + 5c - 20 = 70
6c - 20 = 70
6c = 70 + 20
6c = 90
c = 90/6
c = 15 <=== cost of a CD

t = c - 4
t = 15 - 4
t = 11 .....cost of a tape