gmatkkvinu wrote:The amount of work in a leather factory is increased by 50%. By what per cent is it necessary to increase the number of workers to complete the new amount of work in previously planned time, if the productivity of the new labour is 25% more.
a.60%
b 66.66%
c.40%
d.33.33%
e.80%

We can solve this by plugging in some nice numbers.

We're told that the productivity of the new labour is 25% more.
So, let's say the current workers can produce 4 units/day, which means the new workers can produce 5 units/day.

Let's also say that there are currently 100 workers.

So, 100 workers producing 4 units/per day can produce a total of 400 units.

We're told that the work is increased by 50%.
50% of 400 is 200, so the factory must now produce 600 units.

The current 100 workers are producing 400 units/per day, so the new workers must produce the remaining 200 units.
Since the new workers produce 5 units/day, we'll need need 40 new workers.

In other words, we need to increase the workforce from 100 to 140, which represents an increase of [spoiler]40%[/spoiler]

Answer: C

Cheers,
Brent

Hi JAI SINGH,

This prompt is a poorly-worded GMAT-style question. If you're studying for the GMAT, then it would be best for you to use Official GMAT material (such at the OG13/GMAT2015, the subject-specific books for Quant and Verbal and the software from www.mba.com) and any materials from any credible GMAT Training Companies.

GMAT assassins aren't born, they're made,
Rich