Answer:
110 protons.
Step-by-step explanation:
Alpha particles also known as the alpha radiation which consist 2 protons and 2 neutrons. It is also called as the helium nucleus without electrons. They are basically produced through alpha decay process but there are also other ways to produce it. Like helium nuclei it also have the net spin of zero.
So, the number of protons in a sample with 55 alpha particles will be 110 ( by multiplying 2 with 55 ).