hernandezlarry1234 wrote:

Probability of getting 2 heads and 4 tails when flipping a coin 6 times

hernandezlarry1234,

I'm happy to help.

I saw your post without an answer so far, so I thought I would help.

Think about it this way. In the six flips, how many ways can we place the two heads? We need a combination for this.

See:

GMAT Permutations and CombinationsGMAT Math: Calculating CombinationsHere, the number of ways is 6C2 = 15. There are 15 cases.

In each case, we have six flips, and each one is either H or T. Both have a probability of 1/2, so any one case would have a probability of

\(\frac{1}{2^6} = \frac{1}{64}\)

Since there are 15 cases with identical probabilities, the total probability is

\(\frac{15}{2^6} = \frac{15}{64}\)

This particular setup is known as the Binomial situation in Probability. Here's a free lesson about it:

Binomial SituationDoes all this make sense?

Mike

_________________

Mike McGarry

Magoosh Test Prep

Education is not the filling of a pail, but the lighting of a fire. — William Butler Yeats (1865 – 1939)