At the end of the week, Francesca had a third of her babysitting money left after spending $14.65 on

At the end of the week, Francesca had a third of her babysitting money left after spending $14.65 on a movie and popcorn and another $1.35 on a pen. How much did she earn babysitting?

Let the original amount of money earned for babysitting be b. We're given:

1. Start with b
2. Spending 14.65 for a movie means we subtract 14.65 from b: b - 14.65
3. Spending 1.35 on a pen means we subtract another 1.35 from step 2: b - 14.65 - 1.35
4. Francesca has a third of her money left. So we set step 3 equal to 1/3 of b

b - 14.65 - 1.35 = b/3

Multiply each side of the equation by 3 to remove the fraction
3(b - 14.65 - 1.35) = 3b/3
3b - 43.95 - 4.05 = b

To solve this equation for b, we type it in our search engine and we get:
b = 24