Each working day, the probability of my leaving before 0800 was 0.25. Leaving after 0830 had a probability of 0.10. The probability of arriving late for a tutorial was dependent on my time of leaving home.
These probabilities are given in the following table:
|Time I left my house||Before 0800||Between |
0800 - 0830
|Probability of being late||0.01||0.09||0.9|
I tutored 220 days in 2022. How many times was I late?
The solution is this is best found via a tree diagram.
So the number of times I was late equals
Thirty three times late in a year is not good. I shall have to improve.