SOLUTION: In a scientific study there are 7 guinea pigs, 4 of which are pregnant. If 3 are selected at random without replacement, find the probability that all are pregnant. Enter your answ

Question 1206439: In a scientific study there are 7 guinea pigs, 4 of which are pregnant. If 3 are selected at random without replacement, find the probability that all are pregnant. Enter your answer as a fraction or a decimal rounded to decimal places
Found 2 solutions by ikleyn, greenestamps:
Answer by ikleyn(52803) (Show Source): You can put this solution on YOUR website!
.

P = = = 0.1143 (rounded). ANSWER

Solved.

The formula is self-explanatory.

Answer by greenestamps(13200) (Show Source): You can put this solution on YOUR website!

Or, using another basic method for computing probabilities....

The number of ways of choosing 3 of the 7 guinea pigs is C(7,3); the number of ways of choosing 3 pregnant guinea pigs is C(4,3). The probability of choosing 3 guinea pigs that are all pregnant is

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