How many blue pens were there to start with?

If sin(x) = 0 and cos(x) = 1, what is tan(x)?

Mr. zimmerman invested $25,000 in an account that draws 1.4 interest, compouneded annually. what is the total value of the account after 15 years

Two friends are reading books. jimmy reads a book with 21,356 words. his friend bob reads a book with one-and-a-half times as many words. which expression represents the number of words bob reads?