For this particular question it's better to use smart numbers:
As mentioned in the
MGMAT book, for percentage problems, the best smart number to use is usually 100
So let's assume the total population = 100 persons
25% are miners. Therefore there are 25 people who are miners
16% of the total popluation (be careful here, it's 16% of the total population and not of the miners) are employed miners. That means that there are 16 people that are employed miners
Now the question: What percent of the miners in the town are not employed? (again be careful here, it's asking about the percent of the miners and not the percent of the total population!)
So we know that if there are 16 miners that employed out of 25 total miners, there must be 9 that are not employed.
So the question to answer is the percent of 9 out of the total miners, 25
Once you know what to calculate, the next step is to calculate it as fast as possible. I don't think doing the division directly is the fastest option.
To do it faster, make the denominator 100. If you do that the numerator will automatically be the percent that you are looking for! so:
9/25= (9*4)/(25*4)=36/100
Option EPlease hit the Kudos button if you like the way I approached this problem