Posted by raja harishchandra on Thursday, June 13, 2013 at 1:54am.
A fair coin is flipped 3 times. The probability of getting exactly two heads, given that at least one flip results in a head, can be written as a/b, where a and b are coprime positive integers. What is the value of a+b?

math  raja harishchandra, Thursday, June 13, 2013 at 1:54am
please answer

math  raja harishchandra, Thursday, June 13, 2013 at 2:00am
its urgent

math  Anonymous, Thursday, June 13, 2013 at 2:25am
10

math  Steve, Thursday, June 13, 2013 at 4:56am
10 looks good to me.
Of the 8 possible outcomes, 7 have at least one head
3 of those have exactly 2 heads. 
math  pappu raja, Friday, June 21, 2013 at 6:17am
arre arnav padhai karne lag ja.............tughe ye bhi nahi aaya

math  pappu raja, Friday, June 21, 2013 at 6:18am
chal le tere liye answer...gift..........................2