Question

An experiment calls for a 4% salt solution. Only a 3% salt solution and an 6% salt solution are available. How many gallons of each must be combined to obtain 30 gallons of a 4% salt solution?

1) 3% solution ?
2) 6% solution ?

Answer 1

3% salt solution and an 6% salt solution are  combined to obtain 30 gallons of a 4% salt solution

let amount of 3% solution be x ,

=>amount of 6% solution =30-x

=>(3_/100)x+(6_/100)(30-x) =(4_/100)30

=>0.03x +1.8-0.06x =1.2

=>0.06x -0.03x = 1.8-1.2

=>0.03x =0.6

=>x=0.6_/0.03

=>x=20

amount of 6% solution =30-20= 10

1)amount of 3% solution is 20 gallons

2)amount of 6% solution is 10 gallons

please rate if helpful. please comment if you have any doubt