the human body has about 5.5 liters of blood
3 deciliters is about 0.3 liters
so 5.5/0.3=18.33333
so she could fill 18 and 1/3 glasses before she died
wait
oooooh, she has a supply of blood other than her own, nvm, I should read better
1 decileter is 1/10 of a liter
so 3/10 of a liter per glass
6 of those 2 liter bottles
so total is 6*2=12 liters
so
3/10 times number of glasses=12
times both sides by 10/3
number of glasses=120/3
number of glasses=40
can fill 40 glasses with the blood she is supplied (not including her own)