how can i solve this?prepare 150ml of a 7.5%dextrose sol.you have D5%W and D10%W. how much of each sol. is needed?

I assume the 7.5 dextrose is going to be on a w/w basis also.

This is really simple, no algebra needed. Since 7.5 is halfway between 5 and 10, use equal volumes of the two stock solutions.

Now lets make it harder: Prepare a 9 percent solution.

Let F be the volume of five percent solution
T be the volume of ten percent.

F+T=150
.05F + .10T=.9(150)
Then solve this system of two equations for F, and T.

1 answer

alligation formula.
higher conc 10%
desire conc 7.5%
lower conc 5%
10-7.5 equal 2.5
7.5- 5 equal 2.5
total (2.5+2.5 )=5
2.5:5*150ml=75 ml of D10%W
2.5:5*150ml= 75ml of D5%W