Official Explanation
You need to determine the number of adjunct faculty and the number of nonadjunct faculty in the combined group. According to the graph, 5 percent of the adjunct faculty, or 10, and 10 percent of the non-adjunct faculty, or 25, are in the biological sciences. Similarly, 16 percent of the adjunct faculty, or 32, and 8 percent of the non-adjunct faculty, or 20, are in the health sciences. When you combine the groups, you get a total of 42 adjunct faculty (10 + 32) and 45 nonadjacent faculty (25 + 20), which is a total of 87 faculty. Medical doctors are 1/3 of the 42 adjunct faculty, or 14 adjuncts, and 2/9 of the 45 non-adjunct faculty, or 10 non-adjuncts. Thus, there are 24 medical doctors, and the fraction that are medical doctors is 24/87. The correct answer is (or any equivalent fraction).