MATH Prob.

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a bag contains 7 red chips and 10 blue chips. Two chips are selected randomly without replacement from the bag. what is the probability that both chips are red??

• MATH Prob. -

Work similar to two black cards problem in previous post.

• MATH Prob. -

but how is the answer in decimals??

• MATH Prob. -

You can convert between fractions and decimals - the important part of this question is finding the probability.

• MATH Prob. -

I don't understand.

• MATH Prob. -

The total number of chips in the bag is 7+10 = 17.

The probability of drawing a red chip the first time is (# of red chips)/(total # chips) = _____________

The probability of drawing a red chip the second time, with no replacement, means that you should assume 1 red chip was removed the first time.

The probability of drawing a red chip the second time = (# of red chips -1)/(total # of chips) = ____________

• MATH Prob. -

I still do not get it.
I took (7-1)/17= and I got 0.352
but the answers that I have to choose from are
a) 0.485
b) 0.154
C) 0.515
D) 0.548
I am lost!!!

• MATH Prob. -

You need to use the two probabilities, 7/17 and (since one red has been removed) 6/16. The probability of both occurring is found by multiplying the probabilities of the individual events. Try it, and one answer will pop out for you.

• MATH Prob. -

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