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The average of 10 items was found to be 80 but while calculating, one of the items was counted as 60 instead of 50. Then the correct average would havebeen :
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- 69
- 79.25
- 79
- 79.5
- 69
Correct Option: C
Given that , The average of 10 items = 80
While calculating, one of the items was counted as 60 instead of 50 , then
| Corrected mean = | |
| 10 |
| Corrected mean = | = | ||
| 10 | 10 |
Corrected mean = 79
Second method to solve this question with the help of given formula :
Here, n = 10, m = 80 , a = 50, b = 60
| Correct Average = m + | |
| n |
| Correct Average = 80 + | |
| 10 |
Correct Average = 80 – 1 = 79
