Sarah is purchasing a shirt that is on sale for 20% off. She knows the function that represents the sale price of her shirt is s(p) = 0.8p, where p is the original price of the shirt. She also knows she has to pay 7% sale's tax on the shirt. The cost of the shirt with tax is c(s) = 1.07s, where s is the sale price of the shirt. Determine the composite function that can be used to calculate the final price of Sarah's shirt by solving for c[s(p)].
c[s(p)] = 0.856p c[s(p)] = 0.856sp c[s(p)] = 1.87p c[s(p)] = 1.87sp so that makes 1.87