Question

The average weight of $25$ boys was calculated to be $78.4\, kg$. It was later discovered that one weight was misread as $69$ kg instead of $96 \,kg$. The correct average is

• A. $79\, kg$
• B. $79.48 \,kg$
• C. $81.32 \,kg$
• D. $80.04 \,kg$

Answer 1

Answer: (B)

$79.48 \,kg$

Answer 2

Incorrect sum of all items $= 78.4 \times 25 = 1960\, kg$ $\therefore$ Correct sum $= 1960 - 69 + 96 = 1987 \,kg$ $\therefore$ Correct average $= \frac{1987}{25} = 79.48\,kg$.