Petra wants to buy a skateboard. the skateboard deck usually costs $37.50, but it is on sale for 20% off.

part a. if the sales tax is 5.2% how much will petra pay for the skateboard deck in all? (i have this answer which is $12.3)

part b. if the selling price of $37.50 represents a 20% markup, will the store still make a profit after the 20% markdown? explain.