Melody

The mean is just another word for average.

You have to add up all the numbers and divide by how many there are.

Thank you Chris.

I have given you athumbs up on you diagram too.  

Have you done trigonometry at school Rosala?

Are you saying that you do not understand the question or CPhill's answer?  

If you have done trigonometry at school, and you want to understand this problem then Chris or i can help you understand.  If you haven't done any trig then it will be too difficult for you.

One for each my good Sir!

Please Sir Headless CPhill.  Can we have 2 pictures.  One for this problem and one for you avatar!

P(exactly 2 fives)=(1/6 * 1/6 * 5/6) * 3C2 = 5/216 * 3 = 15/216 = 5/72

P(at least 2 5s) = 1-P(no5s) = 1- (5/6)^3 = 1-(125/216) = 91/216

The above answer is wrong.  Mine is a lest one 5.  CPhill's answer is correct.

P(one5 or two fives)=P(1five)+P(2fives)

= 3C1 * (1/6*5/6*5/6) + 15/216 = 3*25/216 + 15/216 = 90/216 = 5/12

What is this - a mutual admiration society!

It is still not right GoldenLeaf.   

Hi Tavi, 

Let's draw a picure for this.    you see, unless you find the other angle, you must use Cos.

No, this 'guy' is so stupid that s/he is funny.  Why would I want to stomp!

I might stomp on you for that Pythagorean comment that i just corrected!  

Blaming your errors on your school! My goodness!