Answer:
10/40 or a 1 in 4 chance he will grab a red marble
Step-by-step explanation:
You add up all of the marbles;
10+15+15
40
Now you take the number of red marbles are divide it by 40;
10/40
That is your answer.
677777777yyyyyyyyyyyyyyyyyyyyyy
A , because you have to divide it so you can get the correct answer