Problema Solution
how many quarts of pure antifreeze must be added to 8 quarts of a 10 antifreeze solution to obtain a 40% antifreeze solution?
Answer provided by our tutors
let
x = the quarts of pure antifreeze that must be added; we consider the pure antifreeze as a 100% solution.
100% of x antifreeze + 10% of 8 quarts antifreeze = 40% of (x + 8) quarts antifreeze solution
1*x + 0.1*8 = 0.4*(x + 8)
x + 0.8 = 0.4x + 3.2
0.6x = 2.4
x = 2.4 / 0.6
x = 4 quarts
4 quarts of pure antifreeze must be added.