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

[EX Q]: Problem: if a 1 mm thick paper is folded so that the area is halved at every fold , then what would be the thickness of the pile after 50 folds ?
[EX A]: 1 billion km', 'e ) none'

[EX Q]: Problem: what is the units digit of 26 ! + 50 ! + 4 ! + 4 ! ?
[EX A]: 8

[EX Q]: Problem: a train covers a distance of 100 km in 1 hour . if its speed is decreased by 15 km / hr , the time taken by the car to cover the same distance will be ?
[EX A]:
1 hr 10 min