Rocco's friend works at the sporting goods store and gets 10% off the already discounted price. if Rocco's friend buys the golf irons how much will his friend have to pay?

I believe this item should include in the given the original price and the discount per that item apart from the already given. If the original price of the item is p and the discount is d%. The price after the original discount is,

Price = p x (1 - d)

After the additional 10% discount, the price would be,

Price = 0.1 x (p x (1 - d))