A person who has a heart attack can be saved 90% of the time if a defibrillator is used within 5 minutes of the heart attack. Of the people that have heart attacks, defibrillators are within the vicinity 40% of the time; however, they are only used 60% of the time even when they are in the surrounding area.
How many people who suffer a heart attack are saved because of the use of a defibrillator?
Answer(s): B
Explanation:
If a defibrillator is used, we know that the patient will have a 90% success rate; however, only 40% of the people have this option available.
Therefore, we take 0.9 × 0.4 and know that only 36% of the people have this opportunity.
However, we also know that of the 36% of suffers, only 60% of the time is a defibrillator used.
Therefore, we must take 0.6 × 0.36 to find out how many patients are saved by the use of a defibrillator.
This results in 0.216 or 22% of patients are saved by the use of a defibrillator.
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