



 
Hi, 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? Penny
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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