15 men can build a 16.25m long wall upto a certain height in one day. How many men should be employed to build the wall of same height but of length 26 m in one day?

We'll have to use ratio and proportion in this question.

15 men:16.25 m wall in 1 day

Therefore x men:26 m wall in 1 day(Note: x is a variable)

15 : 16.25 :: x : 26

You know that rule about product of means=product of extremes?

Here, 15*26=16.25*x

=390=16.25*x

x=390/16.25=24

Therefore, it will take 24 men to build a 26 m high wall in one day.

Hope it helps.