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when a diver dives, there is a 20% chance of a perfect score. however, if a perfect score is given out, no one else will get a perfect score thereafter. janet is the third diver. what are her chances of receiving a perfect score?

8/10 x 8/10 x 2/10 = 128/1000, therefore 12.8%

my question is why cant we cancel out or simplify the fractions in this problem to make it 4/5x 4/5 x 1/5?

Re: cancelling out [#permalink]
22 Apr 2007, 11:55

bmwhype2 wrote:

this is a probability question.

when a diver dives, there is a 20% chance of a perfect score. however, if a perfect score is given out, no one else will get a perfect score thereafter. janet is the third diver. what are her chances of receiving a perfect score?

8/10 x 8/10 x 2/10 = 128/1000, therefore 12.8%

my question is why cant we cancel out or simplify the fractions in this problem to make it 4/5x 4/5 x 1/5?

I am not sure if I get you. You get the same answer either way

Re: cancelling out [#permalink]
14 Jun 2008, 12:10

bmwhype2 wrote:

this is a probability question.

when a diver dives, there is a 20% chance of a perfect score. however, if a perfect score is given out, no one else will get a perfect score thereafter. janet is the third diver. what are her chances of receiving a perfect score?

8/10 x 8/10 x 2/10 = 128/1000, therefore 12.8%

can someone tell me why we only do one outcome Perfect, Not, Not

and not 2 outcomes Perfect, Not, Not Not, Not, Not

Shouldn't this be 2 outcomes that you add together?

Re: cancelling out [#permalink]
14 Jun 2008, 12:15

h

x-ALI-x wrote:

bmwhype2 wrote:

this is a probability question.

when a diver dives, there is a 20% chance of a perfect score. however, if a perfect score is given out, no one else will get a perfect score thereafter. janet is the third diver. what are her chances of receiving a perfect score?

8/10 x 8/10 x 2/10 = 128/1000, therefore 12.8%

can someone tell me why we only do one outcome Perfect, Not, Not

and not four outcomes Perfect, Not, Not Not, Perfect, Not Not, Not, Perfect Not, Not, Not

Thanks, Ali

Ali,

here the only outcome is NOT, NOT , PERFECT (in that order) since once the Perfect happens it can't happen again and it says that Janet is the 3rd diver