Explanation:
Simplify both ratios in the same way you would simplify a fraction. If they are different numbers, they are not equivalent.
Is 30:70 equivalent to 21:49?
30 and 70 are both divisible by 10, so 30:70 = 3:7.
21 and 49 are both divisible by 7, so 21:49 = 3:7
3:7 = 3:7, they are equivalent!
Is 5:10 equivalent to 6:3?
5:10 = 1:2
6:3 = 2:1
1:2 =/= 2:1, they aren't equivalent!