The average of 45 numbers is 9 The average of the first twenty is 10 and the average of the last twe...........

Quantitative Aptitude ( CCS) Average

The average of 45 numbers is 9. The average of the first twenty is 10 and the average of the last twenty four is 8. Find the 21st number.

total value of 45 numbers is 9 x 45 = 405

total value of first 20 is 10 x 20 = 200

total value of the last 24 is 24 x 8 = 192

405 - 200 + 192 = 13, which is the 21st number.

Hence, option 1 is the correct answer.

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