Question
The average weight of 20 students in a class is 52 kg.
Two students leave the class, and their combined average weight is 40 kg. Subsequently, six new students join the class. After these changes, the average weight of the students decreases by 0.75 kg compared to the original average. Determine the average weight of the six new students.Solution
Total weight of 20 students = 20 X 52 = 1040 kg Total weight of 2 students who left the class = 2 X 40 = 80 kg So, the total weight of 18 remaining students = 1040 - 80 = 960 kg Let the average weight of the 6 new students who joined the class be 'y' kg So, new total weight after 6 new students joined the class = 960 + 6 X y = (960 + 6y) kg New total number of students = 20 - 2 + 6 = 24 New average weight of the 24 students = 52 - 0.75 = 51.25 kg So, we have, (960 + 6y) = 24 X 51.25 Or, 960 + 6y = 1230 So, y = (1230 - 960) Ă· 6 Or, y = 45
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