Answer:
80,000
Explanation:
First, the diameters of both must be in the same unit. Converting the pinhead diameter from millimeter to nanometer, we get:
[tex]2mm = 2*10^6[/tex] nm
To get the number of polio viruses that fit at the head of the pin, divide the pin size by the amount of virus in nanometers:
[tex]2*10^6 = 2,000,000[/tex]
[tex]2,000,000 / 25 = 80,000[/tex]
This concludes that 80,000 polio viruses fit the pinhead.