In a class of 80 students (boys and girls) there are 60% girls. The average weight of the boys is 58 kg and that of the girls is 52 kg. What is the average weight(in kg) of the whole class?
Answer & explanation
Correct answer: option 2
Ratio of number of girls to boys = 3 : 2
Number of girls = \(\frac{3}{5}\) × 80 = 48
& number of boys = 80 - 48 = 32
Total weight = 48 × 52 + 32 × 58 = 2496 + 1856 = 4352
Average weight of whole class = \(\frac{4352}{80}\) = 54.4 kg