18 men can do a piece of work in 20 days. After working for 8 days, they get a notice to complete the work 4 days earlier than originally scheduled. How many more men will be required to be hired to complete the work as per the new schedule?

18 men can do a piece of work in 20 days. After working for 8 days, they get a notice to complete the work 4 days earlier than originally scheduled.

Let's assume the more number of men required to be hired to complete the work as per the new schedule is 'y'.

$$M_1\times\ D_1\ = \ M_2\times\ D_2$$

$$18\times20\ = 18\times\ 8\ +\left(18+y\right)\left(20-8-4\right)$$

$$360\ = 18\times\ 8\ + (18+y)\times\ 8$$

$$360 = 144+144+8y$$

$$360 = 288+8y$$

8y = 360-288 = 72

y = 9

So 9 more men are required to be hired to complete the work as per the new schedule.