The average weight of a certain number of students in a class is 55.5 kg. If 4 students with average weight 60 kg join the class, then the average weight of all students in the class increases by 360 g. The number of students in the class.
Show answer & explanation
Correct answer: A
Explanation
The correct answer is option 1 i.e. 46
Let the number of people be 'n'.
The sum of the weights of n students = 55.5 × n = 55.5n.
Sum of the weights of 4 student = 4 × 60 = 240.
New average = 55.5 + .36 = 55.86
Now according to the question,
55.5n + 240 = 55.86n + 223.44.
.36n = 16.56
n = 46.