If the order matters it is a permutation. For example: if you are selecting 3 people to be on a committee it doesn't matter what order you select them, but if you're selecting three people to be president, vice president, and secretary the order in which you choose them matters the first person being president, the second person being vice president, and the third person be secretary
Let's make an equation. T will be the number. (T+5)/4=7 Let's multiply both sides by 4 to get T by itself. T+5=28 Subtract 5 from both sides. T=23 Your number is 23.
