Number of students in Class

• Mar 5th 2010, 11:20 AM
Number of students in Class
Delete please . . . .
• Mar 5th 2010, 11:34 AM
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The teacher has told the principle that there is :

Half of the students listen to the lesson
1/4 (quarter) of the students looks like they are listining to the lesson
1/7 of the students likes to talk when I'm giving the lesson.
The three left students are sleeping while I'm giving the question.

if we can assume that the students who "look like' they are listening are in fact
not listening and those who are talking are also not listening and do not look like they are listening (each group is seperate)

then, if x is the total number of students

$x\left(\frac{1}{2}+\frac{1}{4}+\frac{1}{7}\right)+ 3=x$