Ricardo spent half of his allowance on school supplies. Then he bought a snack for $5.25. When he arrived home, he had $22.50 left. Which equation and solution represent the amount of Ricardo's allowance, a?

a = 34.5

Step-by-step explanation:

Let's call s, the amount that Ricardo spends on supplies. We know that he spends half his allowance on school supplies so s = 1/2 * a

Next we know he spent 5.25 on a snack and that when he got home he had 22.50 left, so let's include all that information into one equation

So s+5.25=22.50

This can be simplified more because we know that he spends half the total allowance on the school supplies

So 1/2a+5.25=22.50

Now that we have an equation simplify to find a

Subtract 5.25 from both sides:

1/2a = 17.25

Finally, multiply both sides by 2:

a = 34.5