sonya spent 3/8 of her money and had $15 left. how much money did she orginally start with?

If Sonya spend 3/8 of her money, she has (1-3/8)=5/8 left.

Use proportions:
5/8 : $15
1 : $x

Use cross multiplication to get:
$x=$15*1÷(5/8)
=$15*(8/5)
=$24

To solve this problem, we can set up an equation. Let's say "x" represents the original amount of money Sonya started with.

According to the information given, Sonya spent 3/8 of her money, which means she has 5/8 of her money remaining (since 8/8 - 3/8 = 5/8). We also know she has $15 left.

So we can write the equation:

(5/8) * x = $15

To solve for "x," we need to isolate it on one side of the equation. We can do this by multiplying both sides of the equation by the reciprocal of 5/8, which is 8/5:

(5/8) * (8/5) * x = $15 * (8/5)

This simplifies to:

x = $24

Therefore, Sonya originally started with $24.