Question
The average of some natural numbers is 15. If 30
is added to first number and 5 is subtracted from the last number the average becomes 17.5 then the number of natural number is ?Solution
The average of n natural number = 15
New average of n natural numbers = 17.5
ATQ,
(17.5) n = (15)n + 30 – 5
17.5n – 15n = 25
n = 10
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