Question

The average weight of a class of 115 students is 52.4 kg. If the average weight of the 63 boys is 60 kg, then find the average weight (in kg) of the girls in the class. (Rounded off to one decimal place)

• A. 41.8
• B. 45.5
• C. 47.6
• D. 43.2

Answer 1

Answer:

D. 43.2

Total students = 115
Average weight = 52.4 kg

Total weight of all students:

$115\times 52.4 = 6026$

Number of boys = 63
Average weight of boys = 60 kg

Total weight of boys:

63\times 60 = 3780

Number of girls:

115 − 63 = 52

Total weight of girls:

6026 − 3780 = 2246 kg

Average weight of girls:

$\frac{2246}{52}=43.1923\ldots$

Rounded to one decimal place:

43.2 kg