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

[EX Q]: Problem: the average weight of 8 person ' s increases by 3 kg when a new person comes in place of one of them weighing 70 kg . what might be the weight of the new person ?
[EX A]: 94 kg

[EX Q]: Problem: if the radius of a circle is decreased 60 % , what happens to the area ?
[EX A]: 84 % decrease

[EX Q]: Problem: mary can do a piece of work in 26 days . rosy is 30 % more efficient than mary . the number of days taken by rosy to do the same piece of work is ?
[EX A]:
20