There are 50 students in a class. One of them weighing 50 kg goes away and a new student joins. By this the average weight of the class increases by \[\frac{1}{2}\,kg.\] The weight of the new student is |
A) 70 kg
B) 72 kg
C) 75 kg
D) 76 kg
Correct Answer: C
Solution :
Let the average be x. |
Then, sum of weights of all 50 students = 50x |
According to the question, |
\[50x-50+y=50\left( x+\frac{1}{2} \right)\] |
Where y is the weight of new student. |
\[50x-50+y=50x+25\] |
\[-\,50+y=25\]\[\Rightarrow \]\[y=75\text{ }kg\] |
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