Justin and Mike had an equal number of bookmarks. After Justin gave away 20 bookmarks and Mike gave away 33 bookmarks, Justin had 2 times as many bookmarks as Mike. How many bookmarks did each have at first?
Let x = # of book marks Justin and Mike each have at first
x - 20 = 2 (x - 33)
x - 20 = 2x - 66
46 = x