Discussion Forum

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

Answer:

Explanation:

Let the required length be $x$ metres.

More men, More length built  (Direct Proportion)  

Less days, Less length built   (Direct Proportion)

$\left\{\begin{array}{c}Men\quad 20:35\\ Days\quad 6:3\end{array}\right\}::56:x$

$\therefore(20\times 6\times x)=(35\times 3\times 56)$

$\Leftrightarrow\frac{35\times 3\times 56}{120}$ $= 49$.

Hence, the required length is 49 m.