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

[EX Q]: Problem: a cistern 5 m long and 4 m wide contains water up to a depth of 1 m 25 cm . the total area of the wet surface is :
[EX A]: 42.5 m 2

[EX Q]: Problem: in a certain country 1 / 5 of 8 = 4 . assuming the same proportion , what would be the value of 1 / 4 of 16 ?
[EX A]: 10

[EX Q]: Problem: in a group of cows and hens , the number of legs are 16 more than twice the number of heads . the number of cows is :
[EX A]:
8