Posted by **Punkie** on Wednesday, November 18, 2009 at 10:57pm.

Could someone please tell me if I am on track with my answer?

Jack is taking a four-item true-false test. He has no knowledge about the subject of the test and decides to flip a coin to answer the items. What is the probability that he receives a perfect score? What is the probability on a 10-item test?

P(coin being correct in a 4 item t or f test) = 2/4

P(coin being correct in a 10 item t or f test) = 2/10 or 1/5

- math -
**Brittany**, Wednesday, November 18, 2009 at 11:04pm
The chance that you get each question correct is 1/2. To calculate the probability of a perfect score on a 4 question test, you muliply the chance for each correct answer, sooo

1/2 X 1/2 X 1/2 X 1/2 = 1/16

On the 10 question test, it would be

1/2 X 1/2 X 1/2 X 1/2 X 1/2 X 1/2 X 1/2 X 1/2 X 1/2 X 1/2 = 1/1024

- math -
**Punkie**, Wednesday, November 18, 2009 at 11:11pm
Thank you, you really helped me!

- math -
**Brittany**, Wednesday, November 18, 2009 at 11:12pm
Your very welcome!

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