Question
The average weight of 28 students in a class is 40 kg
while the average weight of 5 teachers who teach them is 58 kg. 10 students and 1 teacher go for a trip, and the average weight of the remaining students and teachers is 42 kg and 60 kg respectively. What is the average weight of the group that went on the trip?Solution
ATQ,
10 students and 1 teacher went for the trip which means 18 students and 4 teachers did not go to the trip.
Total weight of 10 students who went for the trip = 40 × 28 – 42 × 18 = 1120 – 756 = 364 kg
Total weight of 1 teacher who went for the trip = 58 × 5 – 60 × 4 = 290 – 240 = 50 kg
Total weight of all the people who went for the trip = 364 + 50 = 414 kg
Required average = 414 / 11 = 37.64 kg
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