[Math] Probability of weighted coin

probability

I'm having trouble with the following question.
A weighted coin lands heads 2/3 of the time whereas it lands tails 1/3 of the time. If the coin is tossed 10 times what is the probability that it will land exactly 4 heads?

I would solve the problem doing (10 choose 4)(2/3)^4(1/3)^6
Kind of like a binomial distribution with probabilities of landing heads = 2/3 and n = 10. Is this correct? Similarly if I wanted to do the P(x<=4) where x is the probability of landing heads I would just sum up the probabilities from 10 choose 0 to 10 choose 4? Thanks guys!

Best Answer

Yes.

(I would have left the answer at that, but the site requires a minimum of 30 characters in an answer. The OP has the right idea in both the "exactly four" and the "less than or equal to four" case.)

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