Question
The average age of a group of 10 people is 50 years. If
the oldest person leaves the group, the average age of the remaining group decreases by 2 years. What was the age of the person who left?Solution
Let the age of the oldest person be y years. Total age of 10 people = 10 x 50 = 500 years. After the oldest person leaves, the average age of the remaining 9 people is 50 - 2 = 48 years. So, total age of remaining 9 people = 9 x 48 = 432 years. Now, Age of the oldest person = Total age of 10 people - Total age of 9 people. y = 500 - 432 = 68 years.
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