On one side of a coin there is the number 0 and on the other side the number 1. What is the probability that the sum of three coin tosses will be 2?
a) 1/8.
b) ½.
c) 1/5.
d) 3/8.
e) 1/3.
I got this problem from a document and don't remember the source. So, I am not 100% sure about the options and the provided answer.
But before looking at the options, I came up with the answer of 1/4. My logic is that we can have only 4 different total: 0,1,2 and 3 from three flips. So the probability of getting a total of 2 is 1/4. Could you please point out where I am making the mistake? I feel that my approach is faulty, but can't figure it out properly. Please help me.
The answer given for this problem is [spoiler](d)[/spoiler].
a) 1/8.
b) ½.
c) 1/5.
d) 3/8.
e) 1/3.
I got this problem from a document and don't remember the source. So, I am not 100% sure about the options and the provided answer.
But before looking at the options, I came up with the answer of 1/4. My logic is that we can have only 4 different total: 0,1,2 and 3 from three flips. So the probability of getting a total of 2 is 1/4. Could you please point out where I am making the mistake? I feel that my approach is faulty, but can't figure it out properly. Please help me.
The answer given for this problem is [spoiler](d)[/spoiler].
Last edited by Uri on Sun Feb 01, 2009 2:28 pm, edited 1 time in total.
