SOLUTION: In a family of 21 people, the average is 14 years. If the age of the grand father is not counted, the average age drops to 12 years. What is the age of the grand father?

Question 768011: In a family of 21 people, the average is 14 years. If the age of the grand father is not counted, the average age drops to 12 years. What is the age of the grand father?
Answer by reviewermath(1029) (Show Source): You can put this solution on YOUR website!
Q:
In a family of 21 people, the average is 14 years. If the age of the grand father is not counted, the average age drops to 12 years. What is the age of the grand father?
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Let x = age of grand father
= 12
14(21) - x = 12(20)
x = 14(21) - 12(20)
x = 54
The age of the grand father is years old.
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