15 to 30 means 15:30, or 15/30. This simplifies to 1/2, which is 1:2.
Just find every answer choice that is equal to 1/2.
1/2 = 1/2
7:15 = 7/15 ≠ 1/2
6/3 = 2/1 ≠ 1/2
4 to 2 = 4:2 = 4/2 = 2/1 ≠ 1/2
10:20 = 10/20 = 1/2
So the correct choices are 1/2 and 10:20.
Hope this helps!
