SOLUTION: A class consisted of 14 boys and 19 girls. On a certain day all the boys was present and some girls were absent, so that the girls present made up only 30% of the class attendance.

Algebra ->  Percentage-and-ratio-word-problems -> SOLUTION: A class consisted of 14 boys and 19 girls. On a certain day all the boys was present and some girls were absent, so that the girls present made up only 30% of the class attendance.      Log On


   



Question 305676: A class consisted of 14 boys and 19 girls. On a certain day all the boys was present and some girls were absent, so that the girls present made up only 30% of the class attendance. How many girls were absent?
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
A class consisted of 14 boys and 19 girls.
On a certain day all the boys was present and some girls were absent, so that
the girls present made up only 30% of the class attendance.
How many girls were absent?
:
Let a = no. of girls absent
:
Total in the class: 14 + 19 = 33 students
then
(33-a) = total in the class on that certain day
:
%2819-a%29%2F%2833-a%29 = .30
19 - a = .30(33-a)
19 - a = 9.9 - .3a
19 - 9.9 = a - .3a
9.1 = .7a
a = 9.1%2F.7
a = 13 girls absent
:
:
See if that makes sense
Total in class that day: 33-13 = 20
Girls in the class that day: 19-13 = 6
6%2F20 = .3 (30%)