Problema Solution
A dehydrated patient needs a 6.8% saline IV. Unfortunately, the hospital only has bags of 4% and 7% saline soulutions. How many liters of each of these solutions should be mixed together to yield 3 liters of the desired concentration?
Answer provided by our tutors
let x lt of 4% be used
so lts of 7% used = 3-x
now we know that
C= (c1v1+c2v2)/(v1+v2)
6.8 = (x*4 + (3-x)*7)/3
20.4 = 21 - 3x
x= 0.2 lt
so lt of 4% used = 0.2 lt
lts of 7% used = 3-0.2 = 2.8 lts