Log in

View Full Version : Probability Homework


helpme123456
Oct 4, 2009, 10:02 AM
Can someone please explain to me how did this happen? Thanks

Question:
In the United States, 43% of people wear a seat belt while driving. If two people are chosen at random, what is the probability that both of them wear a seat belt?

Ans: 18%

Wondergirl
Oct 4, 2009, 10:10 AM
What do you think the percentage should be? (We don't do homework, but will help you figure out stuff after you have done your part.)

helpme123456
Oct 4, 2009, 10:19 AM
I needed someone to explain to me why the answer is 18%. I tried several times to calculate the answer but I can't get the right one. And by the way, this is not a homework. :)

helpme123456
Oct 4, 2009, 10:24 AM
I needed someone to explain to me why the answer is 18%. I tried several times to calculate the answer but I can't get the right one. And btw, this is not a homework. :)

Well actually this was a homework, but it was already checked by our teacher. Now I'm stuck trying to figure out why this happened.

Wondergirl
Oct 4, 2009, 10:24 AM
I needed someone to explain to me why the answer is 18%. I tried several times to calculate the answer but I can't get the right one. And btw, this is not a homework. :)
The heading you posted is "Probability Homework."

Tell me how you calculated.

Unknown008
Oct 4, 2009, 11:02 AM
Yup, I too would like to know how you did it helpme123456... We can't help you if you haven't attempted the question. Since this has been checked, you should know what you did to get this answer!

galactus
Oct 4, 2009, 11:31 AM
Can someone please explain to me how did this happen? Thanks

Question:
In the United States, 43% of people wear a seat belt while driving. If two people are chosen at random, what is the probability that both of them wear a seat belt?

Ans: 18%


Think about it. If the prob. Is .43 for the first person chosen, then wouldn't it be .43 for the second as well? They are independent of one another. That is, the first person does not influence the prob. Of the second person.

(.43)(.43)=

Perito
Oct 4, 2009, 02:35 PM
Can someone please explain to me how did this happen? Thanks

Question:
In the United States, 43% of people wear a seat belt while driving. If two people are chosen at random, what is the probability that both of them wear a seat belt?

Ans: 18%

Start by thinking, "If I pick only one person, what is the probability that the person is wearing a seat belt?". Then, think, "If I pick a second person, what is the probability that he will be wearing a seat belt?"