Antonia and carla have the same percentage of green marbles in their bags of marbles. antonia has 4 green green marbles and 16 total marbles. carla has 10 green marbles. how many of carlas marbles are not green?

Given that Antonia and Carla have the same percentage of marbles and Antonia has 4 green marbles out of 16 marbles , to calculate the number of marbles that Carla has that aren't green we proceed as follows;
let the total number of Carla's marbles be x;
the percentage of green marbles that Antonia has is:
4/16×100=25%

since they have the same percentage then:
number of green marbles Carla has is 10:
this is 25% of x, hence:
10/x×100=25
1000/x=25
1000=25x
thus
x=1000/25
x=40
Carla has a total of 40 marbles. Thus the number of marbles which are not green will be:
40-10=30 marbles

The answer is: a = about 63.59ft2 for 15