Use the following situation for the next few questions:
At Elsa's auto shop, it takes her 12 minutes to do an oil
change and 15 minutes to do a tire change. Let x be the
number of oil changes she does. Let y be the number of tire
changes she does. We are wondering what combinations of
the two tasks she can complete in 60 minutes or less.

1-If Elsa were to only do oil changes, no tire changes, how
many could she do in 60 minutes or less?