It's really important that you aim to understand how to do these problems yourself, rather than "pay" others to do them for you. Why not ask for "directions" or "guidance," instead of for "answers?"
This is a tricky question because it's not required that you have the full 12 beads on the string in every case. You could, for example, have 6 beads, 2 of which would be red, making the ratio of red beads 2 to 6, or 1 to 3.
What about 3 red beads in 9?
What about 1 red bead in 3?
Do these "answers" satisfy the requirement that the ratio of red beads to all beads is 1:3?