How do you perform CPR on an adult?

Performing CPR on an adult involves a specific rhythm of chest compressions and rescue breaths to effectively circulate blood and provide oxygen. The correct approach is to deliver 30 chest compressions followed by 2 rescue breaths. This method adheres to the widely accepted guidelines from organizations such as the American Heart Association and the European Resuscitation Council.

The 30 compressions serve to create pressure within the chest cavity, mimicking the heart's pumping action to circulate blood throughout the body, particularly to vital organs. By following these compressions with 2 rescue breaths, you can provide necessary oxygen to someone who is not breathing adequately. This sequence is designed to maintain a high rate of blood flow while minimizing interruptions in compression, which is key to increasing the chances of survival.

The other choices do not align with the recommended standards for CPR on adults, as they either alter the ratio of compressions to breaths or reduce the number of compressions performed, both of which could hinder the effectiveness of the resuscitation effort.