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

[Q]: Gwen was organizing her book case making sure each of the shelves had exactly 9 books on it . If she had 3 shelves of mystery books and 5 shelves of picture books , how many books did she have total ?
[A]: 72


[Q]: A new building needed 11 windows . The builder had already installed 4 of them . If it takes 8 hours to install each window , how long will it take him to install the rest ?
[A]: 56


[Q]: There were 8 friends playing a video game online when 3 players quit . If each player left had 3 lives , how many lives did they have total ?
[A]:
15