+771 Suppose we flip four coins simultaneously: a penny, a nickel, a dime, and a quarter. What is the probability that at least 15¢ worth of coins come up heads?
I solved it (answer = 5/8) using brute force (E.g. listing out all the combinations) but I feel there must be some more efficient way to solve it. What could it be? Thanks in advance :D
Edit: Changed "brute fort" to "brute force" :)
+639 I agree the only way I know how to do it is brute force, similarly I think CPhill answered this question with the same techqnie as you...
By the way everything below this is 100% CPhill's work even though I used the same methord
16 possible outcomes
P N D Q Value of Heads
H H H H .41
T H H H .40
T T H H .35
T T T H .25
T T T T 0
H T T T .01
H H T T .06
H H H T .16
T H T T .05
T T H T .10
H T T H .26
T H H T .15
T H T H .30
H T H T .11
H T H H .36
H H T H .31
P ( 15 cents or more of heads) = 10/16 = 5/8
