To do this i add them uo and easily subtract woth a hand held calculator
There's only information to answer question C.
We can only know that 32 marbles were chosen. (yellow and black)
Why?
To answer the first two questions (a and b), we need to know the total number of marbles, so, we can only answer the last question (c).
We know that 7/10 of the 20 yellow marbles were chosen.
So, calculating we have:

Also, we know that 18 black marbles were chosen, so, the total of marbles chosen is equal to 32 (yellow marbles and black marbles)

Have a nice day!
You have, on the bottom the number of cars and on the left the corresponding probability.
The probability of having 4 cars is 0.05; the probability of having 5 cars is 0.05 again.
Therefore, the probability of having more than 3 cars is P(4) + P(5) = 0.10 which corresponds to 10%.
The correct answer is 0.10