Answer:
4:8
Step-by-step explanation:
Equivalent ratios have the same simplified ratio.
The simplified ratio of 3:6 is 1:2. We can get it by dividing both sides of the ratio by a common factor of 3.
18:9 is incorrect because its simplified ratio is 2:1. Equivalent ratios have the same order.
4:8 is correct because dividing both sides of the ratio by 4 gives us 1:2.
11:12 is incorrect because it can not be simplified to give 1:2.