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Probability

Sheila either walks or cycles to school
The probability that she walks to school is 0.65
If she walks,the probability that she is late is 0.4
If she cycles, the probability that she is late is 0.1
Work out the probability that on any one day sheila will not be late for school
Original post by XxevexX
Sheila either walks or cycles to school
The probability that she walks to school is 0.65
If she walks,the probability that she is late is 0.4
If she cycles, the probability that she is late is 0.1
Work out the probability that on any one day sheila will not be late for school

Bet Sheila gets a lot of detentions
find out all the probabilities of them being late and then add them all together and take away from 1 to find the answer. (Either use a tree diagram or figure it out with just the numbers.)
Reply 3
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XxevexX
OP
6
So if she walks the probability that she is late is 0.4/0.65 ??
Original post by monkeyman0121
find out all the probabilities of them being late and then add them all together and take away from 1 to find the answer. (Either use a tree diagram or figure it out with just the numbers.)
Original post by XxevexX
So if she walks the probability that she is late is 0.4/0.65 ??


I don't think you divide them, I think you have to multiply them to get the probability she will be late if she walks. After that do that with the probability she is late whilst cycling, add them together and take from 1.
Probability that sheila:
walks=0.65 and is late=0.4;is not late=0.6
cycles=0.35 and is late=0.1;is not late=0.9

so if you need to find the probability of sheila walking and not being late:
0.65*0.6=0.39
AND probability of being not late and cycling:
0.35*0.9=0.315

therefore,the probability of sheila walking or cycling and still not being late:
0.39+0.315=0.705
Reply 6
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XxevexX
OP
6
Thank you 😊
Original post by smiley_21
Probability that sheila:
walks=0.65 and is late=0.4;is not late=0.6
cycles=0.35 and is late=0.1;is not late=0.9

so if you need to find the probability of sheila walking and not being late:
0.65*0.6=0.39
AND probability of being not late and cycling:
0.35*0.9=0.315

therefore,the probability of sheila walking or cycling and still not being late:
0.39+0.315=0.705
Original post by XxevexX
Thank you 😊

That's okay😄

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