# counting rules

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• May 21st 2006, 07:27 PM
skhan
counting rules
A research study was conducted to determine how much the populat "Hukt on Fonics" reading program actually helps young children learn how to read. Three classes, with each class having 10 students, participated in the study. One class did not use the program all the time. After the program, all 30 students rook a reading test, which showed a wide range of scores and no two scores the same.

If you randomly line up the 30 students in a row, what is the probability that they would end up arranged in order of their reading scores from lowest to highest? [3.77E-33]

--> there was a part a and a part B to this question as well which i was able to answer but i cant seem to figure out how to do this last part
thanks in advance
• May 21st 2006, 07:55 PM
ThePerfectHacker
Quote:

Originally Posted by skhan
A research study was conducted to determine how much the populat "Hukt on Fonics" reading program actually helps young children learn how to read. Three classes, with each class having 10 students, participated in the study. One class did not use the program all the time. After the program, all 30 students rook a reading test, which showed a wide range of scores and no two scores the same.

If you randomly line up the 30 students in a row, what is the probability that they would end up arranged in order of their reading scores from lowest to highest? [3.77E-33]

--> there was a part a and a part B to this question as well which i was able to answer but i cant seem to figure out how to do this last part
thanks in advance

Begin by noting,
$\mbox{probability }=\frac{\mbox{favorable outcomes}}{\mbox{possible outcomes}}$
There is only one favorable outcome, i.e. the students lined up. Now we find the favorable outcomes. It is choosing 30 students out of 30 students and order counts thus,
$_{30}P_{30}=30!$
Thus,
$p=\frac{1}{30!}\approx 3.77\times 10^{-33}$

By the way, I think you need to get Hooked on Phonics :D