PSAT Math Grid-Ins Question 81: Answer and Explanation

Question: 81

Group	Proportion
A: inert, mild or no side effects	34.5%
B: inert, moderate side effects	9.2%
C: inert, severe side effects	6.2%
D: drug, mild or no side effects	9.5%
E: drug, moderate side effects	12.8%
F: drug, severe side effects	27.8%

Dr. Hunter is overseeing a treatment-resistant influenza Phase I trial with 400 healthy participants: half are given the drug and half are given an inert pill. The table shows a distribution of the severity of gastrointestinal side effects.

Of those who had severe side effects, what percent were administered the drug? (Round to the nearest whole number and omit the percent sign when gridding in your answer.)

Correct Answer: 82

Explanation:

82

Difficulty: Medium

Getting to the Answer: From the previous question, you know that 264 trial participants did not have severe side effects; therefore, 400 - 264 = 136 participants did. The table indicates that 27.8% of the 400 participants were given the drug and sustained severe side effects, which equates to 0.278 × 400 ≈ 111 participants. So, 111 out of the 136 participants who had severe side effects were given the drug:

Be sure to round this up to the nearest whole percent, as indicated in the question. Grid in 82.