Answer:
I can't see what the options are, but any fraction equal to 1/2 will be equal to 3:6.
Explanation:
Treat a ratio like a fraction. In this case, 3 is the numerator and 6 is the denominator. If you reduce 3/6, you get 1/2. Fractions/ratios also equal to 1/2 or 3/6 are:
2:4
4:8
5:10
6:12
7:14
8:16
9:18
10:20
If any of these ratios are not one of the options, comment below with the choices and I will help you narrow it down.