Solve the problem by writing and using a system of linear equations.
-Find the amount of a 11% saline solution a lab assistant should add to 100 cc (cubic centimeters) of a 21% saline solution in order to have a 16% solution.
A) 0 cc
B) 10 cc
C) 100 cc
D) 150 cc

Question

Quizplus · Accepted Answer

The amount of salt in the original solution is 21% of 100 cc, which is 21 cc. Let x be the amount of 11% saline solution added. The total amount of salt in the new solution is 11% of x plus 21 cc, and the total volume of the solution is 100 cc + x. To have a 16% saline solution, the equation is 0.11x + 21 = 0.16(100 + x). Solving this equation for x gives x = 100 cc.

Solve the Problem by Writing and Using a System of Linear