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Jane needs to make 10 liters of a solution that is 10% salt. She has a solution that is 5% salt and a solution that is 25% salt. How much of each solution should Mia use?

 

Select one:

a. 4 liters of the 5% salt solution and 6 liters of the 25% salt solution

b. 2.5 liters of the 5% salt solution and 7.5 liters of the 25% salt solution

c. 7.5 liters of the 5% salt solution and 2.5 liters of the 25% salt solution

d. 8 liters of the 5% salt solution and 2 liters of the 25% salt solution

 Feb 21, 2019
 #1
avatar+17331 
+1

The total salt in the final solution has to equal the salt from the component solutions

x = liters of 25%        salt content = .25x

10-x = liters of 5 %    salt content = .05(10-x)

 

final solution salt content =  .1 (10) = 1

 

.25x+ .05(10-x) = 1

.25x + .5 - .05x = 1

.20x = .5

x = 2.5 liters of 25%       and  10 -2.5 = 7.5 liters of 5 %

 Feb 21, 2019
 #2
avatar+98126 
+2

Let the no. of liters of 5% solution= x

So...the no. of liters of 25% solution is (10 - x)

 

So.....we have this

 

5 % solution * amt +  25% solution * amt =  10% solution * 10 liters

 

.05 x + .25(10 - x) = .10 * 10   simplify

 

05x  + 2.5 - .25x +  1

 

-.20x + 2.5 = 1     subtract 2.5 from both sides

 

-.20x = - 1.5         divide both sides by .20

 

x = 7.5 liters of 5%  solution

 

And

 

10 - x =  10 - 7.5 =    2.5 liters of 25% solution

 

Answer " C "

 

 

cool cool cool

 Feb 21, 2019

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