The answer to 7 is 11. The error starts in step 1, as you can see youre supposed to do 8 divided by 2 plus 3 times 3 minus 2, instead it seems like 3+3 were added instead of becoming 9 thus the answer becomes 7.
The probability that the marbles are white or grey is 2/8 because since there is 2 marbles and the total is 8 so you have a probability of 25% to get white or gray
