The system: 3 x + 4 y = 40 x + 6 y = 18, ------------------- x = 18 - 6 y 3 ( 18 - 6 y ) + 4 y = 40 54 - 18 y + 4 y = 40 54 - 40 = 18 y - 4 y 14 = 14 y y = $1 x = 18 - 6 x = $12 Answer: Each DVD costs: $12.
Each DVD costs 12 dollars and each book costs 1 dollar
Step-by-step explanation:
I think you meant: David bought 3 DVDs and 4 books for $40 at a yard sale. Anna bought one DVD and 6 books for $18. How much did each dvd and book cost?
