Answer:
16.8
Step-by-step explanation:
you get this by taking the ratio of 12:30 and applying it to 42
you get 30 by taking the total of 12 + 18
you then divide 12 / 30 which equals 0.4
you then multiply 0.4 * 42 which gives you 16.8
if you were to solve for the other ratio you would divide 18 / 30
and then take the answer of that, 0.6 and multiply it by 0.6 * 42
then you have the other part of the ratio.