Question
The average age of a group of 10 students is 30 years.
Two persons of age 12 years and 10 years, left the group and 2 persons of age 20 years and 12 years, joined the group. Find the new average age of the group.Solution
Required average = {(10 × 30) – 12 – 10 + 20 + 12}/10 = 31 years
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