-
ssy
- Senior | Next Rank: 100 Posts
- Posts: 66
- Joined: Sat Sep 29, 2007 7:17 pm
- Thanked: 5 times
- GMAT Score:660
If a coin has an equal probability of landing heads up or tails up each time it is flipped, what is the probability that the coin will land heads up twice on 3 consecutive flips?
0.125
0.25
0.375
0.50
0.666
0.375
I solved this by writing down all the possible outcomes and counting the number of times a coin could land heads up twice out of the total number of outcomes.
I.e.
HHH
TTT
THH
HHT
HTH
TTH
THT
HTT
Is there an easier, less time-consuming way of solving this?
0.125
0.25
0.375
0.50
0.666
0.375
I solved this by writing down all the possible outcomes and counting the number of times a coin could land heads up twice out of the total number of outcomes.
I.e.
HHH
TTT
THH
HHT
HTH
TTH
THT
HTT
Is there an easier, less time-consuming way of solving this?
