Hi sunaimshadmani,
Certain DS questions are more about organization than math-skills. While this question might look complex, it's worth noting that all the references to 4% or 5% are LABELS - they're not part of any calculation that you have to do.
We're told that 25% of the employees at a company give at least 4% of their salaries to a charity. We're asked what PERCENTAGE give at least 5%.
From the prompt, there are a couple of things that you might notice:
1) Since 25% gives AT LEAST 4%....75% give LESS than 4% (and possibly 0%).
2) Since 25% gives AT LEAST 4%.....NO MORE THAN 25% give AT LEAST 5%.
To help organize your information, you might consider TESTing VALUES, so that you can put all of this data in terms of real people. To make things easy, let's say there are 100 total employees. This means that 25 employees gave at least 4% to charity.
Fact 1: 20% of employees contribute 4%-5% to charity.
IF....
Total Employees = 100
25 gave at least 4%
20 gave 4%-5%
25 - 20 = 5 gave MORE than 5%
5/100 = 5%
Changing the total number of employees will have an equivalent effect on the other totals.
IF...
Total Employees = 200
50 gave at least 4%
40 gave 4%-5%
50 - 40 = 10 gave MORE than 5%
10/200 = 5/100 = 5%
The answer is ALWAYS 5%
Fact 1 is SUFFICIENT
Fact 2: 95% of employees contribute LESS THAN 5%
This is really great information, since it tells us about ALL of the employees that we're NOT interested in. 95% gave LESS than 5%.....so who's left? The people who gave 5% OR MORE.
100% - 95% = 5%
Fact 2 is SUFFICIENT
GMAT assassins aren't born, they're made,
Rich