posted by ValeeRo .
You estimate there is an 80% chance you will get an A on your math final, and a 75% chance you will get an A for your semester grade. What is the probability that both will happen?
If the events are independent, the probability of both/all events occurring is determined by multiplying the probabilities of the individual events.
However, they are not independent, since the grade depends on the final.
Is you teacher assuming they are independent?