Problema Solution
at a school camp 30% of the students were boys. When 87 students left the camp after the second day, half of the orignal number of boys were left behind, and the number of girls decreased by 20%. How many girls were at the camp in the beginning?
Answer provided by our tutors
let
x = the number of girls in the beginning or 70% of the camp, x>0
x/0.70 = the total number of students
30% of all the students were boys or 0.3(x/0.7)
the number of girls decreased by 20% means 80% of the girls stayed or 0.80x girls
(1/2)0.3(x/0.7) + 0.80*x = (x/0.70) - 87
by solving we find:
x = 210 girls
click here to see the step by step solution of the equation:
there were 210 girls at the camp in the beginning.