The average of 19 numbers is 22 8 The average of the first ten numbers is 18 4 and that of the last ...........

Quantitative Aptitude (CPO) Average

The average of 19 numbers is 22.8. The average of the first ten numbers is 18.4 and that of the last ten numbers is 28.6. If the 10^th

number is excluded from the given numbers, then what is the average of the remaining numbers? (Your answer should be nearest to

an integer.)

This questions was previously asked in

SSC CPO 13th Dec 2019 Shift-1

- The average of 19 numbers is 22.8, thus the total sum is \(19 \times 22.8 = 433.2\).

- The average of the first 10 numbers is 18.4, meaning their total is \(10 \times 18.4 = 184\).

- The average of the last 10 numbers is 28.6, hence their total is \(10 \times 28.6 = 286\).

- Notice there is overlap at the 10th number. Therefore, \(184 + 286 - x = 433.2\) where \(x\) is the 10th number.

- Solve for \(x\): \(470 - x = 433.2\) giving \(x = 36.8\).

- Excluding the 10th number, the sum of remaining numbers is \(433.2 - 36.8 = 396.4\).

- Hence, the average of these 18 numbers is \(396.4 \div 18 \approx 22\).

Option:3, 22 is the correct answer.

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