The average weight of a group of boys is 20 kg. After a boy of weight 33 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) 12  B) 14  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 33 kg joins the group, total weight of boys = 20x + 33   So 20x + 33 = 21(x + 1) = &gt; x = 12.   12NSWER:12
<result>A</result>
The average weight of a group of boys is 20 kg. After a boy of weight 33 kg joins the group, the average weight of the group goes up by 1 kg. Find the number of boys in the group originally ?