Whats the percentage of somebody getting homework in class there is a 25% chance you get homework in one class 
there is a 40% chance you get homework in another class
what is the probability you get homework in both classes

it is between 0 and 0.25, based on the information you have given. However, if you assume they are independent. i.e. they are two teachers who do not disccuss whether they should give home work on the same day or not
then P(A and B) = P(A)P(B) = 0.25 * 0.4 = 0.1
A is getting work from the 1st class, B is getting work from the 2nd class.
