Math CentralQuandaries & Queries


Question from sujan, a student:

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?


Suppose the total of the ages of the 10 students is $T$ years then

\[\frac{T}{10} = 20.\]

What is $T?$

What is the total of the ages of the 12 students?



When we say the average age of the first 10 students is 20, this means that (A1 + A2 + ... + A10) / 10 = 20

What is (A1 + A2 + ... + A10)?

Write out an equation that says that the average age of the 12 students is 22.

What is (A1+A2+...+A10+A11+A12)?

What is A11 + A12?

What is the average of A11 and A12?

Good Hunting!

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