Which of the following are equivalent ratios?

A: 12 : 16

B: 3 : 5

C: 2 : 3

D: 6 : 8

The equivalent ratios are A and D.

Here's an explanation:

When you look at D, you see that 12 is a multiple of 6, and 16 is a multiple of 8. So you know that it looks like they're equivalent. Then you test it out, 12/2=6. 16/2=8. so 12:16 = 6:8. Eyeballing it first can save time sometimes.