18. During a clothing store's Bargain Days, the regular price for T-shirts is discounted to $8.25.
You have an additional coupon for $5.00 off, regardless of how many shirts are purchased
a. Write a rule for the function p(t) that expresses the final price of t T-shirts with the
discount applied
b. How much would you pay during Bargain Days for 11 shirs?