Angela is writing -you notes. she has 50 notes to write. she writes the -you notes at a rate of 4 notes/hour.

which sketch represents that situation?

Now, she writes 4 notes every 1 hour.

so in 2 hours she has written 8 notes, and the remaining is 50 - 8 or 42.

in 3 hours has written 12 notes, and remaining are 50 - 12, or 38, and so on.

now, how many hours will it take her to them all?  or, how many times does 4 go into 50?  50 /4 or 12.5.

so it will take her 12 hours and a half to do them all, at that time, the remaining notes are 0, because she's done, and the hours are 12 and a half.