For this chain-of-thought reasoning and answer, what was the question?
First find the total number of liters a mosquito sucks in one feeding: 20 drops / 5000 drops / liter = .004 L / feeding. Then divide the lethal amount of blood by the amount of blood one mosquito can drain: 3 L / .004 L / feeding = 750 feedings.
A: 750
Q: A mosquito sucks 20 drops of blood every time it feeds on someone. If there are 5000 drops per liter and you have to lose 3 liters of blood to die, how many mosquitoes would have to feed on you to kill you?