Respuesta :

clarch19

Answer:

dvd cost $12 each

book cost $1 each

Step-by-step explanation:

3d + 4b = 40

d + 6b = 18

substitution method:

d = 18-6b

3(18-6b) + 4b = 40

54 - 18b + 4b = 40

-14b = -14

b = $1

d + 6 = 18

d = $12