Question 53

The average weight of a certain number of students in a group is 54 kg. if 12 students of average weight 52 kg join the group, then the average weight of all the students in the group decreases by 750 g. What was the number of students, initially in the group?

Solution

Let number of students initially = $$x$$

=> Total initial weight = $$54x$$ kg

Weight of new students = $$12\times52=624$$ kg

=> New average = $$\frac{54x+624}{x+12}=53.25$$

=> $$54x+624=53.25x+639$$

=> $$0.75x=15$$

=> $$x=20$$

$$\therefore$$ There were 20 students initially.

=> Ans - (D)

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