### Home > A2C > Chapter Ch10 > Lesson 10.2.5 > Problem 10-130

10-130.

*b* = cost of boards ($) *p* = cost of posts ($) *i* = cost of piers ($)

2*p* + 3*b* + 4*i* = 52

*p* + 5*b* = 13

3*b* − 4*i* = −34

Now, solve the system of equations using elimination.

The boards cost $2, the posts cost $3, and the piers cost $10.