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A boy found that the average of 20 numbers is 35 when he writes a number ‘61’ instead of ‘16’. The correct average of 20 numbers is
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- 32.75
- 37.25
- 34.75
- 34.25
- 32.75
Correct Option: A
Given that , The average of 20 numbers = 35
When a boy writes a number ‘61’ instead of ‘16’ , then
Correct average = 35 + | |||
20 |
Correct average = 35 - | = 35 - 2.25 = 32.75 | |
20 |
Second method to solve this question with the help of given formula :
Here, n = 20, m = 35 , a = 16, b = 61
Correct mean = m + | |
n |
Correct mean = 35 + | |
20 |
Correct mean = 35 - | |
20 |
Correct mean = 35 – 2.25 = 32.75