Question

A fair coin is tossed 3 times. What is the probability of at least two consecutive heads?

$\dfrac{1}{8}$

$\dfrac{1}{4}$

$\dfrac{3}{8}$

$\dfrac{1}{2}$

$\dfrac{3}{4}$

Answer: C

Concepts:basic probability systematic listing

Difficulty rating: 960

Video solution:

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Written solution:

The outcomes with at least two consecutive heads are $HHT$ , $THH$ , and $HHH$ . There are $2^3=8$ equally likely outcomes from three fair coin tosses, so the probability is $\dfrac{3}{8}$ .

Thus, C is the correct answer.

2013 AMC 8 Problem 8

Answer: C

Difficulty rating: 960

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Written solution:

Problem 8 in Other Years