If 20 men can build a wall 56 meters long in 6 days , what length of a similar wall can be built by 35 men in 3 days?
Answer: D
Let the required length be x meters
More men, More length built (Direct proportion)
Less days, Less length built (Direct Proportion)
Men20:35Days6 : 3⋮⋮ 56 :x
=> (20 x 6 x X)=(35 x 3 x 56)
=> x = 49
Hence, the required length is 49 m.