Question
The average of 25 numbers is 22. The average of first 12
numbers is 14 and that of the last 12 numbers is 17. What will be the 25th number?Solution
 Sum of 25 numbers = 25 × 22 = 550 Sum of first 12 numbers = 12 × 14 = 168 Sum of last 12 numbers = 12 × 17 = 204 Therefore, 25th number = 550 – (168 + 204) = 178
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