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counting and probability intermediate

Problem

Coin is flipped three times and coin is flipped four times. What is the probability that the number of heads obtained from flipping the two fair coins is the same?
(A)
(B)
(C)
(D)
Solution
There are ways that the same number of heads will be obtained; , , , or heads. The probability of both getting heads is The probability of both getting head is The probability of both getting heads is The probability of both getting heads is Therefore, the probabiliy of flipping the same number of heads is:
Final answer
D