the coin box of a vending machine contains 28.75 in quarters and loonies, there are 40 coins in total

Question

linear system 

Answer 1

q + l = 40

0.25q + l = 28.75

 

We can solve both for l. The corresponding values will then be equal to each other.

 

l = 40 - q

l = 28.75 - 0.25q

 

40 - q = 28.75q - 0.25q

0.75q = 11.25

q = 15

 

l = 40 - 15 = 25

 

There are 25 loonies and 15 quarters.