The task is to generate the correct answer for a given math problem.

Q: Problem: a number x is 5 times another number y . the percentage that y is less than x is

A: 80 %
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Q: Problem: in what time will a train 50 m long cross an electric pole , it its speed be 360 km / hr ?

A: 0.5
****
Q: Problem: virginia , adrienne , and dennis have taught history for a combined total of 96 years . if virginia has taught for 9 more years than adrienne and for 12 fewer years than dennis , for how many years has dennis taught ?

A:
4
****