A box holds 5 red markers, 3 blue markers, and 4 green markers. If one marker is drawn at random, what is the probability that it is red?

Correct answer to question 46 (Arithmetic Reasoning): 5/12

Method

Probability is the favourable count over the total count. There are 5 red markers out of 5 + 3 + 4 = 12 markers altogether, so the probability is 5/12. Writing 5/7 compares red to non-red instead of to the whole box.