The average weight of a class of 20 students is 44kg. A new student joins the class and the average weight decreases by 300gm. What is the weight of the new student (in kg)?
- A42
- B36.5
- C37.7
- D43.7
Solution & Step-by-step Explanation
Total initial students = 20
Initial average weight = 44kg
When 1 new student joins, the total number of students becomes 21.
The average decreases by 300gm=0.3kg.
New average weight = 44−0.3=43.7kg
Using the formula for the incoming person:
Weight of new student=New Average+(Initial Number of Students×Change in Average)
Weight=43.7+[20×(−0.3)]
Weight=43.7−6=37.7kg
Initial average weight = 44kg
When 1 new student joins, the total number of students becomes 21.
The average decreases by 300gm=0.3kg.
New average weight = 44−0.3=43.7kg
Using the formula for the incoming person:
Weight of new student=New Average+(Initial Number of Students×Change in Average)
Weight=43.7+[20×(−0.3)]
Weight=43.7−6=37.7kg