# Stuck on simple probability question. Need help please

• Oct 18th 2012, 07:01 AM
jeffmama11112
Stuck on simple probability question. Need help please
hi guys i have some homework and im struggling to work out how to do some of these problems:

1) If you flip a coin 3 times. Whats the probability of getting the order: Heads, tails, heads?
• Oct 18th 2012, 07:11 AM
harish21
Re: Stuck on simple probability question. Need help please
Quote:

Originally Posted by jeffmama11112
hi guys i have some homework and im struggling to work out how to do some of these problems:

1) If you flip a coin 3 times. Whats the probability of getting the order: Heads, tails, heads?

how about first writing down the possible outcomes when you flip a coin 3 times?

Hint: when you toss a coin, you have two possible outcomes: H or T. If you toss a coin three times, the tree tosses are independent of each other. So there are 2*2*2=8 outcomes. Write them down
• Oct 18th 2012, 07:18 AM
jeffmama11112
Re: Stuck on simple probability question. Need help please
Thanks harish here are the outcomes (8 OF THEM):
HHH
HHT
HTH
THH
HTT
THT
TTH
TTT
• Oct 18th 2012, 07:30 AM
harish21
Re: Stuck on simple probability question. Need help please
Quote:

Originally Posted by jeffmama11112
Thanks harish here are the outcomes (8 OF THEM):
HHH
HHT
HTH
THH
HTT
THT
TTH
TTT

so out of 8 possible outcomes, you have one outcome that has the order HTH. so you probability is...
• Oct 18th 2012, 07:37 AM
jeffmama11112
Re: Stuck on simple probability question. Need help please
1/8 lol i feel dumb for not knowing that haha. Thanks man
• Oct 18th 2012, 08:43 AM
HallsofIvy
Re: Stuck on simple probability question. Need help please
Another way of doing it: The probability of getting Heads on the first flip is 1/2. The probability of getting Tails on the first flip is 1/2. The probability of tails on the third flip is 1/2. The probability of getting those results on exactly that order is (1/2)(1/2)(1/2).
• Oct 18th 2012, 08:44 AM
jeffmama11112
Re: Stuck on simple probability question. Need help please
Thanks HallsofIv yeh thats another good way of putting it