Rail earns 10% commission on each guitar and 15% commission on each keyboard he sells. In two week he sold 5 guitars that cost$260 each and 2 keyboards that costv$420 each. How much commission did he earn on these seven items?
5 * 260 * 0.1 = ?
2 * 420 * 0.15 = ?
Add the products to find the total commission.