The volume of construction work was increased by 60% but the productivity of labor increased by only 25%. by what percent must the number of workers be increased in order for the work to be completed in time, as it was scheduled originally?

 28 %

Step-by-step explanation:

Volume of a work = productivity × time × number of workers

Let V be the initial volume of the work , x is the initial productivity , n is the initial time and w be the initial number of workers.

Then, V = x × t × n ------ (1)

When, the volume of construction work was increased by 60%, productivity of labor increased by only 25% and time remains same,

Let w' be the new number of workers,

Then, 1.6 V = 1.25 x × t × n' -------(2)

After dividing equation (2) by equation (1),

We get,

Which is the new number of workers.

Thus, the percentage increase in the number of workers =

⇒The number of workers is increased by 28%.