I assume this is a test question. Shame, shame. :)
Unless the rescuer is trained with proper equipment, simply provide compressions. Do not stop for breaths as it is more effective without them.
The bag-mask device is not recommended for a single rescuer to provide breaths during CPR.
What is the compressions to breath ratio for 1-rescuer on infant
maintain an open airway and give breaths
For two rescuer infant CPR; one rescuer should give the breaths, the other rescuer performs compressions using the 2 thumbs encircling hands technique. Give cycles of 15 compressions and 2 breaths.
Maintain an open airway and give breaths.
30:230:230/2
maintain an open airway and give breaths
For an adult, 2-rescuer CPR compression to breath ratio is the same as 1-rescuer; 30 compressions to 2 breaths.
30 compressions per 2 breaths for 1 rescuer adult/child/infant 15 compressions per 2 breaths for 2 rescuer child/infant
30 compressions to 2 vents, for a single person, lay rescuer.
Stays the same for Adult CPR 1 or 2 rescuer; 30 compressions to 2 breaths.
Perform Adult CPR by 30 chest compressions to 2 breaths.