The average weight of a group of boys is 30 kg. After a boy of weight 45 kg joins the group, the average weight of the group goes up by 1 kg. Find the number of boys in the group originally ?  Options: A) 14 B) 15 C) 16 D) 17 E) 18
Let the number off boys in the group originally be x.   Total weight of the boys = 30x   After the boy weighing 45 kg joins the group, total weight of boys = 30x + 45   So 30x + 45 = 31(x + 1) = &gt; x = 14.   14nswer: 14
<result>A</result>
The average weight of a group of boys is 30 kg. After a boy of weight 45 kg joins the group, the average weight of the group goes up by 1 kg. Find the number of boys in the group originally ?