a pharmacist wishes to mix a solution ....

Question

that is 2% minoxidil. she has on hand 70ml of a 1% solution and wishes to add some 4% solution to obtain the desired 2% solution. how much 4% solution should she add?

Answer 1

70 ml (.1) + x ml (.4) = (70 + x) .2

 

7 + .4x = 14 + .2x

 

.2x = 7

 

x = 7/.2 = 35 ml

Answer 2

Say, 4 percent solution is.      = x ml

 

70ml solution is 1 percent

 

x.  ml solution is. 4 percent

 

(70+x). ml solution is 2 percent

 

So,

 

70*1/100. +. 4x/100   =2(70+x)/100

 

70+4x=2(70+x)

 

2x =70

 

x=35 ml

 

So,  35 ml solution of 4percent