how many ounces of pure salt must be added to 16 oz 30% salt solution to produce a 65% solution

Question

idk how to do it 

Answer 1

 

 Let x be the amount of the salt.

 

 The amount of salt in the new solution is

 

 100%* X +  30%*16 = (X+16)*65%

 

Changing the percents to decimals

 

 1*X + 0.3X = (0.65)*(X+16)

 

 1.3X = (0.65)X + 16*0.65 <--- distributive

 

1.3X - 0.65X = 16*0.65

 

0.65X = 10.4

 

X = 16

 

16 ounces of salt is needed

 

CHECK:

 

30% of 16  = 4.8 oz of salt was in the old solution.

There is now 16+4.8 oz of salt in 16+16 oz of the new solution.

 

20.8/32 = 0.65 = 65%