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Popular Word Problems >

A fair coin is tossed 7 times. What is the probability that all tosses will be tails?

Solution

A f ai r co in i s t osse d 7 t im es . Wha t i s t h e p ro babi l i t y t ha t a ll t osses w i ll b e t ai l s ?

Solution

\frac{1}{128}

+1

Decimal

0.0078125

Solution steps

The possible outcomes when a coin is thrown

7

times are

2 \cdot 2 \cdot 2 \cdot 2 \cdot 2 \cdot 2 \cdot 2

Therefore, the number of possible outcomes:

2^{7}

Find the number of favorable outcomes of all tosses will be tails:

1

Probability

= \frac{number of favorable outcomes}{total number of outcomes}

= \frac{1}{2 ^{7}}

2^{7} = 128

= \frac{1}{128}

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