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The average of a certain group of students is 50.5. Fifty-four and a half students left the group and one student with 72.5 joined the group. Now the average increases by 1.5. Find the current number of students in the group.

1. 21
2. 29
3. 27
4. 19

Correct answer: 21

Solution

Let the original number of students be n. The average increases by 1.5, so the new average is 52.0. Using the net change in total marks due to the students who left and joined, the current number of students comes out to be 21.

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