Question

A drug trial is testing the effectiveness of two drugs. If 50 patients are given Drug A, 20 patients are given Drug B, and 100 patients are given a placebo, what is the probability that a patient will NOT be given a placebo?
A. 5/17
B. 10/17
C.2/17
D.7/17

Answer 1

So, to find the answer you'd first add up how many patients you have:
20+50+100 = 170.
In a fraction your total would go on the bottom. Then you'd take how many patients are taking a real drug, which is represented by 20+50 = 70. This number would go on top.

So, the probability of a patient NOT getting a placebo is 70/170. Simplified would be 7/17. 

The answer is D. 7/17.