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

[EX Q]: Problem: jack and jill are marathon runners . jack can finish a marathon ( 42 km ) in 7 hours and jill can run a marathon in 4.2 hours . what is the ratio of their average running speed ? ( jack : jill )
[EX A]: 5 / 5

[EX Q]: Problem: there are 2 red chips and 3 blue ones . when arranged in a row , they form a certain color pattern , for example rbrrb . how many color patterns ?
[EX A]: e ) 10

[EX Q]: Problem: pipe a can fill a tank in 6 hours . due to a leak at the bottom , it takes 12 hours for the pipe a to fill the tank . in what time can the leak alone empty the full tank ?
[EX A]:
1