The ratios in an equivalent ratio table are 3:12, 4:16, and 5:20. If the first number in the ratio is 10, what is the second number? Justify your reasoning.

The multiplier is 4 (3*4=12, 4*4=16), so 10*4 is 40, therefore the ratio is 10:40

I believe the answer would be 10/40. First, I simplified all of the given rations. You do this by finding the two numbers greatest common factor. For example, 3/12, 3 goes into 3 once and 3 goes into 12 four times. So that ratio would be 1/4. If you continue the pattern you would get 1/4 for all of them. Therefore, 10/40 would be correct since it's ratio would also be 1/4.