Derek has 7 times as many stickers as Larry. If Derek gives 30 stickers to Larry, the two people will have exactly the same amount. How many stickers do they have altogether?
Together, they have 80 stickers.
let x be the amount of sticker that Larry has;
That means that Derek has 7x stickers. To get both Derek and Larry to have an equal amount of stickers, you will have to subtract 3x from 7x which is the amount that Derek has, so then they both have 4x stickers. Since Dereck gave 3x stickers, and he also gave 30 stickers, that would been that x = 10. In the begining, if Larry had x stickers, and Derek had 7x stickers, that would mean that together they have 8x stickers, and since x = 10, that means that together they have
8(10) = 80 stickers.
Sorry for the long explanation.