Answer:
White: 1/4
Red: 1/3
Black if 24 counters: 5/12 or 10 counters.
Explanation:
White is 90 degrees. A circle in total has 360 degrees.
so the fraction of whites in the bag is 1/4 or 0.25
Same logic with the red:
The fraction is 1/3 or 0.33(3)
Now, if the white is 1/4 and the red is 1/3 then the fraction of blacks is:


If total is 24 then all we have to do is find 5/12 of 24.
.
And that's the answer to the third question