7. Tyler's brother works in a shoe store. a. Tyler's brother earns a commission. He makes 2.5% of the amount he sells. Last week, he sold $900 worth of shoes. How much was his commission? b. The store bought a pair of shoes for $50, and sold it for $80. What percentage was the markup? c. Tyler's brother earns $12 per hour. The store offers him a raisea 5% increase per hour. After the raise, how much will Tyler's brother make per hour