A store sells 2 1/4 pounds of mulch for every 1 1/2 pounds of gravel sold. The store sells 180 pounds of mulch and gravel combined. How many pounds of each items does the store sell?
Let m = pounds of mulch
g = pounds of gravel
We can set up two equations:
m + g = 180 ----> g = 180 - m
(9/4)m = (3/2)g
Substitute the value of g on the second equation:
(9/4)m = (3/2)(180 - m)
(9/4)m = (3/2)(180) - (3/2)m
Multiply through by 4 to get rid of the fraction:
9m = 6(180) - 6m
9m + 6m = 6(180)
15m = 6(180)
15m = 1080
m = 72
Put that value back into the first equation:
72 + g = 180
g = 180 - 72
g = <<108=108>>108
The store sells 72 pounds of mulch and 108 pounds of gravel. Answer: \boxed{72,108}.