A bag contains 7 red marbles, 12 orange marbles, 18 yellow marbles, and 5 purple marbles. A marble is drawn at random from the bag.

What is the probability that the marble drawn will not be orange?

First you add together all of them to get the denominator. 7+12+18+5 is 42.

then you need to add together the non-oranges or take away the oranges from the total. 42-12 is 30 so the probability to get a marble that is not orange is 30/42

15/21.

First determine the total number of marbles.

7+12+18+5 = 42 total marbles.

Then determine how many are not orange.

42-12 = 30 marbles are not orange

Then divide the number that are not orange by the total number

30/42 = about 70% chance it will not be orange