The ratio of gas cars to hybrid cars in the school parking lot is 15: 4. There are 12
hybrid cars in the parking lot. How many
gas cars are in the parking lot?

The salesperson earns a 5% commission on the first $5,000 she has in sales. the salesperson earns a 7.5% commission on the amount of her sales that are greater than $5,000. this month the sales person had $8,000 in sales. what amount of commission, in dollars, did she earn?