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.

[Q]: Sara goes fishing with Melanie . Sara catches 5 trout . Melanie catches 2 times as many trout as Sara . How many trout did Melanie catch ?
[A]: 10


[Q]: At lunch a waiter had 7 customers and 4 of them did n't leave a tip . If he got $ 9 each from the ones who did tip , how much money did he earn ?
[A]: 27


[Q]: A painter needed to paint 12 rooms in a building . Each room takes 7 hours to paint . If he already painted 5 rooms , how much longer will he take to paint the rest ?
[A]:
49