Anita has 2 sisters and 3 brothers. The mean of all their ages is 6yrs.What will their mean age be 10yrs from now?20 yrs from now?

Answer 1

So, there is 5 siblings total. If you add up all there ages and divide by 5, you get 6. What can you divide by 5 to get 6?
When you get "that number", you can age the siblings however you want to get "that number" as your total. The, keep finding the mean by adding 10 and 20 years to all their ages.

Answer 2

720