Answer:
R
Explanation:
Let's rewrite this to the ratio of the amount of cents to the amount of people.
9 cents every 4 people -> 9:4
18 cents for every 8 people -> 18:8
Using the direct proportion : If one quantity increase/decrease an amount, the other one increase/decrease the same amount respectively.
So, we can rewrite 9:4 as 9x2/4x2 (both increase by 2 times) = 18:8
And since 18:8=18:8, these 2 ratios are equivalent.