A statistics math problem, I need help with

I need to develop an equation expressing the following

16% failure rate if you study
3% failure rate if you show up to class

What would be the failure rate if you studied and showed up to class?

 

I think you want to build equations for this system in x and y variables. right?

I think it should be for failure rate:-

number of total students x 0.16

and ffor don't show up to class:-

number of total students x 0.13

 

Failure rate if you didn't study and you didn't show up to class:
0.16 + 0.13 = 0.29 (29%)

 

my try:
x * 16/100 = 16x/100
16x/100 * 13/100 = 16x * 13 / 100 * 100

 

This (x) + Thread (y) = Fail

 

It depends. Arguably students could be included in either category because if they don't turn up to class they're not studying. Assuming the categories are meant to be separate and students fall in either one or the other, the percentage failure rate would just be A + B since the denominator (/100 in a %) is the same in both cases.

(where A = % who didn't study; B = % who didn't attend)

 

= F either way

 

In my school 100%

 

lol some of the replies to this thread are quite funny. especially House Ovaries thread

 

lawl, thanks man. =]

 

I actually wrote the problem incorrectly. Edited in OP.

 

Yes, you can.
If you think about it a percentage is a fraction with a denominator (divided by) of 100. It's no different at all to adding 1/4 + 2/4 + 1/4 = 1.

 

failure rate if you studied and showed up to class
0.16 X 0.03 = 0.0048 (0.48% failure rate)

 

Ahh, that complicates matters.
Still, for future reference you can combine percentages directly as I said!

 

Are you looking for a regression table or some other bell curve using a SD (standard deviation) based on the 97,68, and 32% graph?

 

Nope, I'm looking for a formula to figure out the failure rate.

 

This is what I assume.

Both the events are independent events.
Probability of A is 16/100
Probability of B is 3/100

Therefore, probability of ( A and B ) is given by = 16/100 * 3/100 = 48/10,000 = .0048

 

Please see my post earlier on.
The failure rate if you studied and showed up to class is 0.48% --
consistent with gr8liverpoolfan's analysis.

 

Thanks, you guys. This really helps me out. Hey Mel03, this is weird but I used to have a username of Melanie03 (I graduated HS in 03)