Do you know how to do math very well?

Question

Ok, I have this math problem I cannot figure out!

During a recent school survey of two middle school classes, 1/3 of the students reported that they bring their lunch to school. Another 1/4 reported that they buy their lunch in the cafeteria and 1/6 reported going home for lunch. The remaining 18 students reported that they don't eat lunch. How many students are in the two classes?

PLEASE HELP!

Answer 1

Follow me and it'll be easy! 'n' would be the total number of students. And x would be multiplication

Brings lunch=1/3 x n
Buys lunch=1/4 x n
Goes home= 1/6 x n
Don't eat=18

You see, if all of these numbers add up, it should be the total number of students, which is n.
So, (1/3)n+(1/4)n+(1/6)n+18=n
(9/12)n+18=n
(3/4)n+18=n
18=n-(3/4)n
18=(1/4)n
multiply 4 on both sides 72=n

72 students. !

Answer 2

First find how much of the class was surveyed by adding together the fractions:

1/3+1/4+1/6

=4/12+3/12+2/12
=8/12
*simplify*

=2/3

THEREFORE we need to find out how much of the class WASN'T surveyed

1-2/3
=1/3
THEREFORE 1/3 of the class is 18 students

SO

if 1/3 is 18 students, and we need to find how many is in ONE WHOLE, we add 18 together 3 times:

1/3 of the class+1/3 of the class+1/3 of the class
=18 + 18 +18
=54 students in the two classes

Answer 3

72

Answer 4

33.48