Test Index

Probability

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Question : 68 of 127

Marks: +1, -0

If an unbiased coin is tossed three times, what is the probability of getting more that one head?

$\frac{1}{8}$
$\frac{3}{8}$
$\frac{1}{2}$
$\frac{-1}{3}$

Solution:

Concept:

Probability =

\frac{\text{favorable outcomes}}{\text{total outcomes}}

.

Explanation:

Total outcomes when tossing a coin three times:

2^3 = 8

.

More than one head means 2 or 3 heads.

Number of ways to get exactly 2 heads:

\binom{3}{2} = 3

.

Number of ways to get exactly 3 heads:

\binom{3}{3} = 1

.

Total favorable outcomes =

3 + 1 = 4

.

Probability =

\frac{4}{8} = \frac{1}{2}

.

Answer:

\frac{1}{2}

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