If 20 men can build a water fountain 56 metres long in 3 days, what length of a similar water fountain can be built by 35 men in 3 days? Choose the correct choice from the following answers
A) 40 m
B) 64 m
C) 77 m
D) 89 m
E) 98 m
Explanation :   Let the required length be x metres   More men, More length built (Direct Proportion)   Less days, Less length built (Direct Proportion)   Men 20: 35   Days 3: 3 : : 56 : x   Therefore (20 x 3 x x)=(35 x 3 x 56)   x=(35 x 3 x 56)/60=98   Hence, the required length is 98 m.   Answer : 98 m
<result>E</result>
If 20 men can build a water fountain 56 metres long in 3 days, what length of a similar water fountain can be built by 35 men in 3 days?