Question

The average weight of a group of 53 girls was calculated as 58 kg. It was later discovered that the weight of one of the girls was read as 65 kg, whereas her actual weight was 45 kg. What is the actual average weight of the group of 53 girls? (rounded off to two digits after decimal)

• A. 58.62
• B. 58.37
• C. 57.37
• D. 57.62
• E. None of these

Answer 1

The correct option is E None of these

Here, value of new quantity added - value of removed item = $\pm$ N
$\Rightarrow$ 45 - 65= $\pm$ 53 $\times$ x
$\Rightarrow$ + 20 = + 53 $\times$ x
$\Rightarrow x=\frac{23}{53}$
So, actual average $=58-\frac{20}{53}$
= 58 - 0.37
= 57.63