Help with a physics problem...?

Question

1. normally, women possess about 4.5 million of red blood cells in each cubic millimeter of blood.

if the blood flow to the heart organ is 250 mL/min how many red blood cells does a woman's heart receive each second?

Answer 1

1 mL = 1000 mm^3, 1 min = 60 sec.

Therefore the flow is 250 mL/min * (1000 mm^3/mL) * (min/60sec) = 4167 mm^3/sec.

Now multiply that by the 4.5 million red blood cells per mm^3 and you get: 1.875 x 10^10 red blood cells every second.

That's 18.75 Billion red blood cells every second. Amazing!