To solve this we have to create an equation, and since all of the number of songs that people have are described in terms of how many more songs than lou they have, lou will be X, If kelly has 4 times as many songs as Lou that would be 4x, tiffany has 6 times as many songs as lou, she will have 6x:
Let be the number of liters of the 10% solution she needs to use. She'd end up with a 6% solution with a volume of liters. The starting solution contains 0.04*9 = 0.36 liter of salt. Each liter of the 10% solution contributes 0.1 liter of salt, so that
Solve for :
so Mayra needs to add 4.5 liters of the 10% solution.
