The mean of 100 items was 60 . Later it was found that two items were misread as 69 and 96 instead of 66 and 99 respectively. The correct mean of the 100 items is

Question

The mean of 100 items was 60 . Later it was found that two items were misread as 69 and 96 instead of 66 and 99 respectively. The correct mean of the 100 items is (A)  60  (B)  61  (C)  60.5  (D)  61.5

Tardigrade Admin · Accepted Answer

Incorrect mean = 60, Incorrect sum = 6000 ∴ Correct sum = 6000 -69 - 96 + 66 + 99 = 6000 ∴ Correct mean = (6000/100) =60

Q. The mean of $100$ items was $60$ . Later it was found that two items were misread as $69$ and $96$ instead of $66$ and $99$ respectively. The correct mean of the $100$ items is

$60$

$61$

$60.5$

$61.5$

Incorrect mean $= 60$ ,
Incorrect sum $= 6000$
$∴$ Correct sum $= 6000 - 69 - 96 + 66 + 99$
$= 6000$
$∴$ Correct mean $= \frac{6000}{100} = 60$

Q. The mean of 100 items was 60 . Later it was found that two items were misread as 69 and 96 instead of 66 and 99 respectively. The correct mean of the 100 items is

60

61

60.5

61.5