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 β 2 + 5 = 9 New average age = 81/9 = 9 years
Evaluate:
β729 + β49 - β16 + 1/β64
Simplify:

(1/5)(40% of 800 β 120) = ? Γ 5
2/5 of 3/4 of 7/9 of 7200 = ?
`sqrt(5476)` + 40% of 1640 = ? `xx` 4 - 2020
? = (22% of 25% of 60% of 3000) + 21
Determine the simplified value of the given mathematical expression.
(342 β 20% of 5280) = ? Γ· 3
β157464 =?