Stuart paid $48.00 for a new tennis racket, which was 64% of the original price.

Okay. I believe for this question, we are looking for the original price. With $48 being paid for on a tennis rack, 64% of the original price was paid. To find the original price of the rack, we can write and solve a proportion. Set it up like this:

48/x = 64/100

This is because 48 is part of a whole and represents 64% of the original amount. We will now solve this problem. Cross multiply the values. 100 * 48 is 4,800. 64 * x is 64x. That makes 4,800 = 64x. Now, divide each side by 64 to isolate the x. 64x/64 cancels out. 4,800/64 is 75. Let's check this. 75 * 64% (0.64) is 48. There. The original price was $75.