Question

36 men together can build a wall 140 m long in 21 days ; the number of men working at the same rate required to build the same wall in 14 days is

Answer 1

Solution :-

Let the required number of men be 'x'.

As the length of the wall and the rate of working is same, but days are less then the number of men required will be more to build the 140 m long wall in 14 days.

This is the case of indirect proportion.

⇒  Men  36  :   x 
                              : : 140 : 140
              21  :  14   
 
⇒ (36*21*140) = (x*14*140)

⇒ 1960x = 105840

⇒ x = 105840/1960

⇒ x = 54 men

Hence, to build 140 m long wall in 14 days, 54 men will be required working at the same rate.