In a bag of red and yellow cookies, the ratio of red cookies to yellow cookies is 4:5. If the bag contains 80 yellow cookies, how many red cookies are there?
There would be 64, because if there are 4/5 as many red cookies as yellow cookie, then you divide the amount of yellow cookies, in this case 80, by five, which is 16. So if 1/5 is 16 then multiply it by 4 to find what 4/5 equals: 16 x 4 = 64
