Lisa has 12 more stickers than john, and together they have 60 stickers. what is the ratio of the number of lisa’s stickers to the number of john’s stickers?

You can work this several ways. One way is to figure out how many stickers each has, then write their relationship as a ratio.

Here, Lisa will have 12/2 = 6 more than half the total number of stickers, hence 36. John will have the remaining 24. Their ratio is
  Lisa's stickers : John's stickers = 36 : 24 = 3 : 2

Another way to look at this is to realize 12 divides 60 into 5 equal parts. The ratio that will total 5 parts with one number being 1 larger than the other is 3 : 2.
  Lisa's stickers : John's stickers = 3 : 2