Quadratic thing I got the answer but i need like a step by step explanation because i dont get it :/

If your teacher tells you to do questions 6 through 19 in your math book for homework, how many questions is that

Find an bif a = {3, 6, 9, 12) and b = {2, 4, 6, 8, 10).

For the chance to be team captain, the numbers 1-30 are put in a hat and you get two chances to pick a number, without replacement. which formula correctly shows how to find the probability that you choose the number 1 and then 2?