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Question

Rachel is setting up a 20-gallon saltwater fish tank that needs to have a salt content of 3.5% If Rachel has a container of water that has 2.5% salt content and another container of water that has 3.7% salt content, how many gallons of water with the 3.7% salt content should Rachel us?

Answer 1

Let x = amount of water with 3.7% salt and then 20-x = amount of water with 2.5% salt.

 

.037x + .025(20-x) = .035(20)

 

.012x + .5 = .7

 

.012 x = .2

 

x = 16 2/3 gallons