The average weight of a group of boys is 30 kg. After a boy of weight 37 kg joins the group, the average weight of the group goes up by 1 kg. Find the number of boys in the group originally ?
Choose the correct option.
A) 4 B) 8 C) 5 D) 2 E) 6
Let the number off boys in the group originally be x.   Total weight of the boys = 30x   After the boy weighing 37 kg joins the group, total weight of boys = 30x + 37   So 30x + 37 + 31(x + 1) = &gt; x = 6.   Answer: 6
<result>E</result>
The average weight of a group of boys is 30 kg. After a boy of weight 37 kg joins the group, the average weight of the group goes up by 1 kg. Find the number of boys in the group originally ?