You get 25% discount and pay 40 what is the original price

Acar dealership pays you 5% commission on your first $10,000 on car sales and 8% commission on the sale amount over $10,000 if you sold a $12,000 car how much is your commission

If 1/√5+1/√5+1=p+q√r , find the values of p, q and r

Can someone check if i did this right since i really want to make sure it’s correct. if you do you so much