I need someone to check my answers please

S

Shinnola

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Apr 30, 2007
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As you drive north on Broadway, you have a 40% probability of having to stop at the traffic light at the intersection with Ricoter Road.

1) What is the probability you will not have to stop on any such drive?
I did 1-.4=.6=60%
Is this right?

2) If you drive north on broadway every day for a week, what is the probability you will have to stop all seven times?

I did 1 * 0.6^0 * 0.4^7=.0016384
Is this correct?

3) What is the probability you will have to stop none of the seven times?

This is the method I used.

P(0) = 1 * 0.6^7 * 0.4^0=.0279936
Is this correct?

4) Show how you calculate the probability you will have to stop exactly three of the seven times.

Method:
P(3)= 35 * 0.6^4 * 0.4^3=.290304
Is this correct

I would really appreciate your help.
 
1) Correct.

2) I'm not sure why you're including the factors "1" and "0.6<sup>0</sup>" (which is another form of "1")...? But the final expression is, I believe, correct, other than needing to convert it into percentage form.

3) The answer should probably be in percentage form.

4) Where did the "35" come from? (I'm not saying it's wrong -- I don't know.)

Thank you.

Eliz.
 
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