Please help due in 10 minutes! At a skateboard shop (Answer numerically only. Units have been provided):

a. The price tag on a shirt says $12.58. Sales tax is 7.5% of the price. How much will you pay for the shirt? $

b. The store buys a helmet for $19.00 and sells it for $31.50. What percentage was the markup? %

c. The shop pays workers $14.25 per hour plus 5.5% commission. If someone works 18 hours and sells $250 worth of merchandise, what is the total amount of their paycheck for this pay period? $