UCAT/ UKCAT Question Analysis - Decision Making Question 2
This year, 40% of the population received the flu vaccine. Yet, 70% of the populatiobn caught the flu. Which of the following MUST be true?
A. At most 10% of those vaccinated caught the flu.
B. At least 25% of those vaccinated caught the flu.
C. At most 10% of the population was vaccinated and caught the flu.
D. At least half of those who were not vaccinated stayed healthy.
Answer and Explanation:
B. At least 25% of those vaccinated caught the flu.
This type of question is often BEST solved by using simple graphs.
![broken image](http://custom-images.strikinglycdn.com/res/hrscywv4p/image/upload/c_limit,fl_lossy,h_9000,w_1200,f_auto,q_auto/4979856/483280_802912.png)
By juxtaposing graphs in accordance with each option, you can determine whether each statement is correct or not.
From Graphs 1 and 3, we know that those who caught the flu have to re[resent at least 40% - 30% = 10% of the population. This is equivalent to 10/40 = 25% of the vaccinated population.
Take a look at the other options:
A. At most 10% of those vaccinated caught the flu.
From Graphs 1 and 2, it is possible that all 40% vaccinated actually caught the flu. So, we can't say that most 10% of those vaccinated caught the flu as it could be as high as 100%.
C. At most 10% of the population was vaccinated and caught the flu.
We know from the reasoning used for A that this could be as high as 100%. However, it is true that AT LEAST 10% of the po;ulation was vaccinated and caught the flu.
D. At least half of those who were not vaccinated stayed healthy.
Graphs 1 and 3 show that it is possible that all non-vaccinated people caught the flu. However, AT MOST half of those who were not vaccinated stayed healthy.
Drafted by Quincy (UCAT Prep)
Photo Reference: https://www.quivermanagement.com/improved-decision-making/