Question
The average age of a group of six children is 8 years.
From the group, two children, whose ages were 2 years more and 4 years more than the average age, left. Five new children, whose average age is 3 years more than the given average age, join the group. Find the new average age.Solution
Initial sum of the ages of 6 children = 8 x 6 = 48 years Ages of the children leaving: 8 + 2 = 10 years and 8 + 4 = 12 years, Sum of the ages of children leaving = 10 + 12 = 22 years Sum of the ages after two children left = 48 - 22 = 26 years Sum of the ages of 5 new children = (8 + 3) x 5 = 55 years Total sum of the ages with new children = 26 + 55 = 81 years Number of children now = 6 – 2 + 5 = 9 New average age = 81/9 = 9 years
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