SOAR Academy Practice Exam

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If two coins are flipped, what is the probability of getting at least one head?

3/4

With two coin flips, each flip is independent and has two equally likely outcomes. The possible results are HH, HT, TH, and TT. “At least one head” includes all outcomes except the one with no heads (TT), so there are three favorable outcomes out of four, giving a probability of 3/4.

Another way to see it is by using the complement: the chance of no heads is both tails, which is (1/2) × (1/2) = 1/4. Subtracting from 1 yields 1 − 1/4 = 3/4.

The other options don’t fit because 1/2 is the chance of a head on a single flip, 1/4 is the chance of both tails, and 1 would mean a guaranteed head appears, which isn’t the case with two fair coins.

1/2

1/4