How many positive integers less than 500 are equal to 5 times an even integer?
I want to find all the numbers of the form 5(2k) that are less 500, where k is a positive integer. I can rewrite this inequality as 10k < 500, and divide both sides by 10 to get k < 50. So k can range from 1 to 49, and there are 49 such values of k. Therefore, there are 49 positive integers less than 500 that are equal to 5 times an even integer. 