At a factory a baseball card is placed in every 9th package of cereal. A football card is placed in every 25thpackage of the cereal. What is the first package that gets both a baseball card and a football card

The first time a package will contain both is the Lowest Common Multiple of both numbers (9 and 25). These two numbers are prime to each other (meaning there is no common factor other than 1), so the answer is

9 * 25 = 225

So on the 225 package the box will contain 1 baseball card and 1 football card.