You are given a math word problem and you are supposed to apply multiplication or division mathematical operators on the numbers embedded in the text to answer the following question and then only report the final numerical answer.

Each chocolate bar in a box cost $ 3 . If a box had 7 bars total and Olivia sold all but 4 bars , how much money would she have made ?
9

There are 3 calories in a candy bar . How many calories are there in 5 candy bars ?
15

While playing a trivia game , Mike answered 3 questions correct in the first half and 5 questions correct in the second half . If each question was worth 3 points , what was his final score ?

24