79.(b)this is because you have six choices, 3 red, 1 blue, 1 yellow, and 1 green and since it says not red you only have 3 choices, blue yellow and green, so the fraction would be 3/6. You can simplify the fraction by dividing it by 2 and you would get 1/2.
80.the answer will still be (b) which is the same explanation for 79.
81. (C) because remember that the first time you only had a 50% (1/2) chance of getting red and the second chance of getting a red will be the same but not
Its not likely You can get a red.