In the Hillside summer camp there are 50 children. 80% of the children are boys and the rest are girls. The camp administrator decided to make the number of girls only 10% of the total number of children in the camp. How many more boys must she bring to make that happen?  Choose the correct choice from the following:
A) 55
B) 50
C) 40.
D) 30.
E) 25.
Given there are 50 students , 80% of 50 = 40 boys and remaining 10 girls.   Now here 80% are Boys and 20% are Girls.   Now question is asking about how many boys do we need to add, to make the girls percentage to 20 or 20%..   If we add 50 to existing 40 then the count will be 90 and the girls number will be 10 as it.   Now boys are 90% and girls are 10%. ( out of 100 students = 90 boys + 10 girls ).   IMO option 50 is correct.
<result>B</result>
In the Hillside summer camp there are 50 children. 80% of the children are boys and the rest are girls. The camp administrator decided to make the number of girls only 10% of the total number of children in the camp. How many more boys must she bring to make that happen?