Sarah earns $20 per hour during the week and $30 per hour for overtime on the weekends. One week she earned a total of $650. She worked 5 times as many hours during the week as she did on the weekends. How many hours of overtime did she have?

Given:

20 per hour during the week

30 per hour overtime on the weekends

earned a total of 650.

20 (5x) + 30x = 650

100x + 30x = 650

130x = 650

x = 650/130

x = 5 overtime

5x = 5 (5) = 25 hours during the week.

20 (25) + 30 (5) = 650

500 + 150 = 650

650 = 650