The average weight of a group of boys is 35 kg. After a boy of weight 40 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 most appropriate option: A) 4 B) 5 C) 6 D) 7 E) 8
Let the number off boys in the group originally be x.   Total weight of the boys = 35x   After the boy weighing 40 kg joins the group, total weight of boys = 35x + 40   So 35x + 40 = 36(x + 1) = &gt; x = 5.   Answer: 5
<result>B</result>
The average weight of a group of boys is 35 kg. After a boy of weight 40 kg joins the group, the average weight of the group goes up by 1 kg. Find the number of boys in the group originally ?