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When a person needs a minicab, it is hired from one of the three firms, X, Y and Z. 
The 40% of the hiring are from X, 50% are from Y and 10% are from Z, for the cabs hired from X, 9% arrive late, 
the corresponding percentages for the cabs hired from firms Y and Z being 6% and 20% respectively. 
Calculate the probability that the next cab hired:
(1) Will be from X and will not arrive late.
(2) Will arrive late given that a call is made for a minicab and that it arrives late, that it came from Y.
(1)   P = 0.4*(1-0.09) = 0.4*0.91 = 0.364.    ANSWER
(2)  Question (2) in the post is formulated incorrectly.
     In that form as it is given in the post, it is simply soup of words, inappropriate for use (inedible).
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           |   It MUST be re-written to make sense.    |
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     How it should be done, it is a care of the Math composer, not mine.
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Part (1) is solved. 
Part (2) is defective.