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

[EX Q]: Problem: set s contains exactly 10 numbers and has an average ( arithmetic mean ) of 6.2 . if one of the numbers in set s is increased by 7 , while all other numbers remain the same , what is the new average of set s ?
[EX A]: 6.

[EX Q]: Problem: a bullet train covers a distance in 50 min , if it runs at a speed of 48 kmph on an average . the speed at which the bullet train must run to reduce the time of journey to 40 min will be .
[EX A]: 60 kmph

[EX Q]: Problem: robert ' s salary was decreased by 20 % and subsequently increased by 20 % . how much percentage does he lose ?
[EX A]:
4 %