Question
The average weight of 9 students in a seminar is 42 kg.
If the weight of 4 facilitators is also included, then the new average weight of each person (facilitator + student) in the seminar becomes 48 kg. Find the average weight of the four facilitators.Solution
ATQ, Let the average weight of the four facilitators be 'x' kg. So, total weight of the four facilitators = 4 × x = '4x' kg. ATQ: 42 × 9 + '4x' = 48 × (9 + 4) Or, 378 + 4x = 48 × 13 Or, 378 + 4x = 624 Or, 4x = 624 - 378 = 246 Or, x = 246 ÷ 4 = 61.5 Therefore, the average weight of the four facilitators is 61.5 kg.
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