8. One of the Roman dice in the British Museum has 6 square faces and 8 triangular faces. It is twice as likely to land on any given square face as any given triangular face. What is the probability that the face it lands on is triangular, when thrown?

Question

unklerhaukus · Answer

the probability is the number of favorable outcome divided by the total number of outcomes

anonymous · Answer

Huh? yes but what is the answer to the question? or how would i work it out?

anonymous · Answer

Basics:
The prob of landing on any particular square face is equal to the probability for any other square face.  They are all equal.

The prob of landing on any particular triangular face is equal to the probability for any other triangular face.  They are all equal.

OK with that?

anonymous · Answer

Let P(one particular triangular face) = p
Then what is the total probability of landing on any one of the triangular faces?

anonymous · Answer

You there?

anonymous · Answer

sorry back mate, was having dinner

anonymous · Answer

back

anonymous · Answer

Total prob of landing on any tri face = 6p
Prob of landing on any one square face = 2p
Total prob of landing on any square face = 12p
Total prob of landing on any face = 6p + 12p = is defined to be equal to 1

anonymous · Answer

Gotta go.

anonymous · Answer

okie doke cheers for the help mate ;)

anonymous · Answer

Thankyou very much

anonymous · Answer

the available answers were (A)4 (B) 3 (C)3 (D) 3 (E)2 7 11 7 10 5

anonymous · Answer

oh hold on
one sec sorry wrong ones

anonymous · Answer

uhhh they are all fractions, cant post them

anonymous · Answer

And I messed up, 8 triangular faces
Total prob of landing on any face = 8p + 12p = is defined to be equal to 1
p = 1/20
can you do it now?

anonymous · Answer

a) 4/7 b) 3/11, c) 3/7, d) 3/10, and e) 2/5

anonymous · Answer

uhh im having a go again now

anonymous · Answer

8 tri faces each with a p = 1/20
total p if it could be any tri face = 8/20

anonymous · Answer

yes that works, that means the answer is e 2/5

anonymous · Answer

Yes.

anonymous · Answer

gosh i see how easy it is now, my calculus is easier than that... problem solving is not my strong point

anonymous · Answer

i really appreciate it

anonymous · Answer

yw

anonymous · Answer

i have a nation wide maths competition tomorrow. I can do conventional maths like calculus/trig/ whatever else reasonably well, but i cannot problem solve, and all fo these questions are multi choice problemsolving