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
In the future you can go to desmos graphing calculator
The vector field

has curl

Parameterize
by

where

with
and
.
Take the normal vector to
to be

Then by Stokes' theorem we have



which has a value of 0, since each component integral is 0:




The answer is A....a=5 b=30