A laboratory technician needs to make a 99-liter batch of a 20% acid solution. How can the laboratory technician combine a batch of an acid solution that is pure acid with another that is 10% to get the desired concentration? The laboratory technician can combine Lof the pure acid solution with L of the 10% acid solution to get the desired concentration.

a laboratory technician needs to make a 90% liter batch of a 20% acid solution. How can the laboratory technician combine batch of an acid solution that is pure acid with another that that is 10% to get the desired concentration.

a laboratory technician needs to make a 90 liter batch of a 20% acid solution.

How can the laboratory technician combine batch of an acid solution that is pure acid with another that that is 10% to get the desired concentration

:

Let x = amt of pure acid

the result is to be 90 liters, therefore

(90-x) = amt of 10% solution required

:

.10(90-x) + x = .20(90)

9 - .1x + x = 18

.9x = 18 - 9

.9x = 9

x = 9/.9

x = 10 liters of pure acid required

then

90 - 10 = 80 liters of the 10% solution required

:

:

See if that checks out

.10(80) + 10 = .20(90)

8 + 10 = 18; confirms our answer