So we notice that they increase by 1 each time first slot we have all of them so 4 choices=1st slot 3 choices=2nd slot (1 was taken for 1st slot) 2 choices 1 choice multiply 4 times 3 times 2 times 1=24 answe ris 24 ways
From the other answer, I see that my colleague with the busted clock interpreted your question in a different way. So I should explain how I understand your question.
I understand you to say that both English sections meet at the same time, all 3 math sections meet at the same time, all 3 History sections meet at the same time, and all 4 Biology sections meet at the same time. So our student will take the subjects in that order, but for each period, she can choose which section to join. If that's not the right way to understand the question, then it's definitely too complicated for me.
Reading it MY way, here's the solution:
English: 2 choices. For each of those . . . Math: 3 choices. For each of those . . . History: 3 choices. For each of those . . . Biology: 4 choices.
