Average weight of a group of 20 boys was calculated to be 89.4 kg and it was later discovered that o

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The average weight of a group of $20$ boys was calculated to be $89.4 kg$ and it was later discovered that one weight was misread as $78 kg$ instead of the correct one of $87 kg$. The correct average weight is in $kg$

A

$88.95$

B

$89.25$

C

$89.55$

D

$89.85$

Solution

Total weight of 20 boys $=89.4 \times 20=1788 kg$

Increase in weight due to misreading $=87-78=9 kg$

Correct weight of 20 boys $=1788+9=1797 kg$

Correct average weight $=\frac{1797}{20}=89.85 kg$

Standard 13

Quantitative Aptitude

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