SOLUTION: A student studying for a vocabulary test knows the meanings of 14 words from a list of 20 words. If the test contains 10 words from the study list, what is the probability that at

Algebra ->  Probability-and-statistics -> SOLUTION: A student studying for a vocabulary test knows the meanings of 14 words from a list of 20 words. If the test contains 10 words from the study list, what is the probability that at       Log On


   

Question 952314: A student studying for a vocabulary test knows the meanings of 14 words from a list of 20 words. If the test contains 10 words from the study list, what is the probability that at least 8 of the words on the test are words that the student knows? (Round your answer to three decimal places.)

Answer by edjones(8007) About Me  (Show Source):
You can put this solution on YOUR website!
14/20=.7, 1-.7=.3
nCr=10C8=10!/((10-8)!*8!)=45
45*.7^8*.3^2
=.233
.
10C9=10
10*.7^9*.3
=.121
.
.7^10
=.028
.
.233+.121+.028
=.383 (rounding error) the probability that at least 8 of the words on the test are words that the student knows.
.
Ed