5 of 8 is 62.5%
13 of 22 is 59.09%
22 of 30 is 73.33%
12 of 25 is 48%
Store 3 has the greatest percentage of smartphones
I would go about solving this by elimination because the x variables are already the same so all you would have to do is change one equation to the opposite signs and add them, so it would look like:
7y + 5x = 19
+ -3y - 5x = -7
-------------------
4y=12
y=3
