+77
The probability of a fine day is 3/7 and the probability of a wet day is 4/7.
If it is a fine day:
The probability that a man cycles to work is 7/10.
The probability that a man drives to work is 2/10.
The probability that a man takes the train to work is 1/10.
If it is a wet day:
The probability that a man cycles to work is 1/9.
The probability that a man drives to work is 5/9.
The probability that a man takes the train to work is 3/9.
If he works 315 days a year, how many days is he likely to drive to work?
