The average weight of a group of boys is 20 kg. After a boy of weight 32 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 choice from the following answers:
A) 12
B) 11
C) 18
D) 24
E) 10
Let the number off boys in the group originally be x.   Total weight of the boys = 20x   After the boy weighing 32 kg joins the group, total weight of boys = 20x + 32   So 20x + 32 = 21(x + 1) = &gt; x = 11.   ANSWER:11
<result>B</result>
The average weight of a group of boys is 20 kg. After a boy of weight 32 kg joins the group, the average weight of the group goes up by 1 kg. Find the number of boys in the group originally ?