This GMAT quant practice question is a problem solving question from statistics and averages. Concept: Computing arithmetic mean of new elements added to a set of data.

#### Question: The average age of a group of 10 students was 20. The average age increased by 2 years when two new students joined the group. What is the average age of the two new students who joined the group?

- 22 years
- 30 years
- 44 years
- 32 years
- None of these

#### Video Explanation

Scroll down for explanation text#### Explanatory Answer

Description | Number | Average | Sum |
---|---|---|---|

Initially | 10 | 20 | 200 |

After 2 students join | 12 | 22 | 264 |

Weight of 2 new students | 264 - 200 = 64 kg |

The average age of a group of 10 students is 20.

Therefore, the sum of the ages of all 10 of them = 10 * 20 = 200

When two new students join the group, the average age increases by 2. New average = 22.

Now, there are 12 students.

Therefore, the sum of the ages of all 12 of them = 12 * 22 = 264

Therefore, the sum of the ages of the two new students who joined = 264 - 200 = 64

And the average age of each of the two new students = \\frac{64}{2}\\) = 32 years.

Choice D is the correct answer.

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