I would say this is correct, I'm still wondering about this one:240 * 240 =57600 .. .. so 1 in 57,600

240 / 3 = 80 ... 80 * 80 = 1 in 6,400

Results 1 to 9 of 9

- March 11th 2011, 12:44 PM #1

- Joined
- Jul 2009
- Posts
- 49

## are they having an affair?

me and my friend at work have been having a debate .

there is a man and women at work that everyone suspects is having an affair.

one day out of the blue

they both phoned in sick on the same day , my friend said ,what are the odds of that happening ,

i started to wonder........

i said well if there are**240**working days in a year , and they both have**exactly 1**day off a year

it would be**240 * 240 =57600 .. .. so 1 in 57,600**

but if they both had**exactly 3 days off a year**it would be

**240 / 3 = 80 ... 80 * 80 = 1 in 6,400**

**he disagrees**

i know there are other things to consider like , we dont know exactly how many

days they both have off a year

but if the cases are as above ,the math is correct i think ?

- March 11th 2011, 01:13 PM #2

- Joined
- Feb 2011
- Posts
- 11

- March 11th 2011, 01:28 PM #3

- Joined
- Jul 2009
- Posts
- 49

yes im wondering to about that one!

im also wondering if there is a formula to work out these type of questions , for instance we dont no for sure

how many days people have off sick a year , maybe the average is , say 5... is there a formula to work it out from that...

my working out is scrappy at most ,

- March 11th 2011, 01:54 PM #4

- Joined
- Feb 2011
- Posts
- 11

Hmm, I modified it a little bit to make it easier to look at.

Instead I'm looking at 5 possible days in which the 2 workers can sick at once.

This gave me 1 in 5.

I would maybe even say that this:

240 * 240 =57600 .. .. so 1 in 57,600

So the result for this:

240 / 3 = 80 ... 80 * 80 = 1 in 6,400

- March 11th 2011, 01:57 PM #5
You need to study the Birthday Problem.

Scroll down to the probability discussion.

What is the probability the lady picks a different leave day?

- March 11th 2011, 02:16 PM #6

- Joined
- Jul 2009
- Posts
- 49

no... i think your wrong ..... but i dont know for sure but i think that if there are 240 working days

and they both have exactly 1 day off a year .....and they pick the same day it is 240 *240 = 57,600

and if they both have exactly 3 days each off a year , it is 1 in 6,400

that they pick the same day

they are independent

the day he chooses to have sick, does not effect the day she chooses

- March 11th 2011, 02:31 PM #7

- Joined
- May 2006
- From
- Lexington, MA (USA)
- Posts
- 12,002
- Thanks
- 822

Hello, jickjoker!

There is a man and women at work that everyone suspects is having an affair.

One day out of the blue, they both phoned in sick on the same day.

My friend said, "What are the odds of that happening"

i started to wonder . . .

[edit]

But if they both had exactly**3**days off a year . . .

The man can have3 days-off of the 240 working days.*any*

Consider the probability that the woman hasof the days-off that the man has.*none*

There are: . possible choices.

To avoid the man's days-off, she must select 3 of the other 237 days.

. . There are: . ways.

The probability that the man and woman have at least one day-off together

. . is: . . . . or about 1 in 27.

~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Stop arguing . . . Plato is absolutely correct!

If they each haveday-off per year,*one*

. . the reasoning goes like this.

The man can haveday-off . . . It doesn't matter.*any*

What is the probability that the woman has the same day-off?

. . Answer: .

Your answer involving is a different problem.

What is the probability that the man and woman take**June 23rd**off?

Get it?

- March 11th 2011, 02:37 PM #8

- Joined
- Feb 2011
- Posts
- 11

Isn't that just the number of combinations and not the chance that they are sick on the same day.

Hmm maybe if we think like this:

Think about a number between 1 and 240, what are the chances of me guessing right? Well that would be 1 in 240 .. Let say I failed to guess the number.

Now think about a number between 1 and 240, what are the chances of me guessing right? Still 1 in 240.. It doesn't matter what number you pick or how many times I guess, my chances are still 1 in 240.

Same goes for Male Worker and Female Worker. It doesn't matter what day the Male Worker is sick, because the chances of the Female Worker also being sick is 1 in 240.

I might be right, I might be wrong.

- March 11th 2011, 02:40 PM #9

- Joined
- Jul 2009
- Posts
- 49