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The average of 20 numbers is 12. The average of the first 12 numbers is 11 and that of the next 7 numbers is 10. The last number is :
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- 40
- 38
- 48
- 50
- 40
Correct Option: B
Here , Sum of 20 numbers = 20 × 12
sum of first 12 numbers = 11 × 12
sum of next 7 numbers = 7 × 10
∴ Last number = Sum of 20 numbers – sum of first 12 numbers – sum of next 7 numbers
Last number = 20 × 12 – 11 × 12 – 7 × 10
Last number = 240 – 132 – 70 = 38
