Question

If 20 men can build a wall 56 meter long in 6 days what length of a similar wall can be built by 35 men in 3 days

Answer 1

Let the required length be x meters

 More men, More length built     (Direct proportion) 

Less days, Less length built      (Direct Proportion)

men 20:35
days 6 : 3

 (20 x 6 x X)=(35 x 3 x 56) 

=> x = 49