GMAT Question of the Day - Data Sufficiency - Overlapping Sets 1
At a certain company, 1/3 of the employees are senior managers and 2/3 of the employees are full-time. If 1/5 of the full time workers contribute to the company retirement plan, how many of the full-time employees contribute to the company retirement plan?
(1) Exactly 120 of the employees are senior managers
(2) Of the full-time employees, 3/4 of them are not senior managers
GMAT Question of the Day Solution:
For overlapping sets with 2 groups (in this case Senior Managers and Full Time Employees) use a chart (see below). Take your time organizing the information. Read carefully.
Overlapping sets Strategies and Organization:
1. It helps to make 1 chart per statement so that you don't confuse the information. Using one chart and erasing the information from the first statement so that you can evaluate the second statement is a chaotic waste of time. In this case I didn't make a chart for statement (2) because I could clearly see that it was insufficient.
2. If you don't have a total then make that a variable. I always use T.
3. Use a box to highlight the space in the chart that you are solving for. Here I put a question mark above the box but only for demonstration purposes. Avoid putting a question mark in your chart - it's messy and takes up space.
4. Last thing - avoid doing calculations in the box. Do those off to the side and then fill in the chart with the values.