Answer:
They sold 40 bags of hardwood and 116 bags of pine bark.
Step-by-step explanation:
Let x be the amount of hardwood bags they sold and y be the amount of pine bark bags they sold. We can use this to set up an equation:
x+y=156
2.5x+1.75y=303
Let's change the first equation into:
x=156-y
We can solve using substitution (substitute 156-y for x)
2.5(156-y)+1.75y=303
390-2.5y+1.75y=303
390-0.75y=303
Subtract 390 from both sides
-0.75y=-87
Divide both sides by -0.75
y=116
x=156-y
x=156-116
x=40
They sold 40 bags of hardwood and 116 bags of pine bark.