The total number of marbles will be 35 + 8 + 7 = 50 marbles in total (all the colors added together). The probability of drawing a red marble will be the number of red marbles divided by the total marbles. This also fits the probability formula of (desired outcomes)/(total number of outcomes. Thus, we have 35 red marbles and 50 marbles in total. So, we get 35/50, which is 70%.
