There are two groups C and D of a class consisting of 32 and 40 students, respectively. If the average weight of group C is 60 kg and that of group D is 33 kg, then find the average weight of the whole class.
Show answer & explanation
Correct answer: A
Explanation
The correct answer is option 1 i.e 45 kg.
Group C: 32 students, average weight = 60 kg
Group D: 40 students, average weight = 33 kg
Total weight of each group
Group C: 32 × 60 = 1920 kg
Group D: 40 × 33 = 1320 kg
Total students = 32 + 40 = 72
Total weight = 1920 + 1320 = 3240 kg
Average = 3240 ÷ 72 = 45 kg