There are 50 boys in a class. Their average weight is 45 kg. When one boy leaves the class, the average reduces by 100 g. Find the weight of the boy who left the class.  Choose the correct choice from the following choices
A) 40.9 kg  B) 42.9 kg  C) 49.9 kg  D) 39.9 kg  E) None of these
Here one boy is excluded and final average of the group decreases.   ∴ change in average is (–)ve = – 0.1 kg.   Using the formula   Sum of the quantities excluded   =(49.9 kghangein no.ofquantities×Origina lAverage)+(49.9 kghangeinAverage×Final no.ofquantities)   ⇒ weight of the boy who left = (1 × 45) – (– 0.1 × 49)   = 49.9 kg   Answer 49.9 kg
<result>C</result>
There are 50 boys in a class. Their average weight is 45 kg. When one boy leaves the class, the average reduces by 100 g. Find the weight of the boy who left the class.