medium · GMAT Quant
A customer support analytics team tracks call resolution times across two shift teams operating with equal average call durations. Shift 1 handled 40 calls with a variance of 25 minutes^2. Shift 2 handled 60 calls with a variance of 100 minutes^2.
What is the combined variance of call resolution times, in minutes^2, for all 100 calls?
- 62.5
- 70
- 55
- 125
- 7000
Sign up free to see the explanation and track your rank →
More GMAT Quant practice
- Including both endpoints, how many distinct integer price points are in this range?
- Which of the following expressions must result in a positive value?
- Which property of arithmetic justifies that first step?
- Which of the following must also be an even integer?
- Which of the following inequalities correctly represents this range?
- Which of the following includes the number 0?
- How many unique meal combinations can a customer create?
- What is the probability that the lightbulb is functional?