Question

Nancy is very happy with the service at the hotel she is staying in. She wants to tip the room service waiter 15 percent of the food bill, which is $120.75. How much should she tip

Answer 1

Foodbill *15%

Answer 2

You need to calculate 15% of $120.75.

In math, "of" often means "times" as in multiplication.
Also, % means /100, divided by 100.

15% of $120.75 = 15/100 x $120.75 = 0.15 x $120.75