Joanne was making repairs to her deck and needed to buy some supplies. She purchased two posts, three boards, and four piers for $52. Needing more materials, she went back to the lumberyard and bought one post and five boards for $13. Realizing she did not need the piers she made a third trip where she bought three more boards, returned the four piers and ended up with a refund of $34. What was the cost of each item? Homework Help ✎
b = cost of boards ($) p = cost of posts ($) i = cost of piers ($)
2p + 3b + 4i = 52
p + 5b = 13
3b − 4i = −34
Now, solve the system of equations using elimination.
The boards cost $2, the posts cost $3, and the piers cost $10.