Question

3. When Caha needs a taxi, she rings one of three taxi companies A,B or C. 50% of her calls are to taxi company A, 30% to B and 20% to C. A taxi from company A arrives late 4% of the time, a taxi from company B arrives late 6% of the time and a taxi from company C arrives late 17% of the time.
i. Find the probability that when Caha rings for a taxi, it arrives late
ii. Given that Caha’s taxi arrives late, find the conditional probability that she rang company B

Answer 1

i) P required = 0.5*0.04+0.3*0.06+0.2*0.17 = 0.072

Answer 2

im gonna instruct u and u gonna do it

Answer 3

Ok.

Answer 4

first calculate and add all the probabilites that the taxi is late

Answer 5

Callisto did that :)

Answer 6

ok u shud do second part by urself , cause i want u to learn , altho i d help u

Answer 7

Yes, I need to learn!

Answer 8

so u done?

Answer 9

order i will give u a really good concept that will help u every time in conditional probabilty
listen what ever is written after given that will go into denominator
and what ever is written before or after that will go into numerator

Answer 10

So, 0.018 will go in denominator? The condition that B arrives late... and numerator?... is 0.072... the total?

Answer 11

That doesn't make sense... mmm help?

Answer 12

:P listen jus temme what is written after given that?

Answer 13

She rang B sorry..

Answer 14

so got it now?

Answer 15

not completely... I know that the conditional probability is
CP= \[(a given b)\over b\]

Answer 16

But... I don't know how to apply that rule?

Answer 17

ok do as i say now :P , temme what is written after given tht?

Answer 18

Given that she rang B

Answer 19

no no c it is written that caha taxi arrives late ,c

Answer 20

Oh!

Answer 21

and what ever etc is written would go in numerator, like in this case, caha rang taxi and it arrived late

Answer 22

so, would that mean the numerator is 0.06 time 0.3?

Answer 23

or... not?

Answer 24

nooooo numerator would b .2*.06

Answer 25

why 0.2?

Answer 26

because the probability of caha calling taxi company b is .2, and the taxi getting late is .06

Answer 27

But... the probability is 0.3 from 30% for company b?

Answer 28

ohhh LOl i read it wrong, order u are rite

Answer 29

great :) Thanks! So, it would be that over 0.072

Answer 30

yup yup , btw whats ur name cox its wierd calling u order lol

Answer 31

I prefer not to use my name on websites... just for security purposes... but you can call me Nikki if you want

Answer 32

ohhh ok nikki or nikita too :P

Answer 33

Lol. sure.

Answer 34

ok nikita :P

Answer 35

Thanks for your help!1

Answer 36

pleasure :)