Mark bought a new bookcase with 5 shelves. Each shelf will hold twice as many books as each shelf on the old bookcase. What is the total number of books that will be on the new bookcase when it is full?

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?