Sunny is x years old.
Bea is one year younger than Sunny.
Joey is double Sunny’s age.
The mean of their ages is 5
How old is Joey?
Answer:
If Sunny’s age is x then Bea’s age is one less so can be written as (x-1)
And Joey’s age can be written as 2x
To find the mean you must add up all the values and divide by the number of values
This gives you (x + x – 1 + 2x)/3 which simplifies to (4x-1)/3
Since the mean is 5 you can do (4x-1)/3=5
Then solve the equation to get 4x-1 = 15
Then 4x = 16 meaning x = 4
Since Joey’s age is 2x he is 8