Question

75% and 90% pure solutions are mized to obtain 40 litre of 81% pure acid solution. Find the
quantity of each type of acid to be mixed to form the mixture.​

Answer 1

Answer:

Let the quantity of 90 percent solution be x and 97 pure acid be y liters.

According to question, we can write

x+y=21   ...(i)

x×10090+y×10097=(x+y)×10095

⇒90x+97y=(x+y)95

⇒90x+97y−95x−95y=0

⇒−5x+2y=0  ...(ii)

Multipliying equation (i) by 2 we get,

   x+y=21

   2x+2y=42  ... (iii)

Subtraction equation (ii) by (iii) we get,

   2x+2y=42

   −5x+2y=0 

                            

   7x=42

    x=6

Putting the value in equation (i) we get,

x+y=21

⇒x+y=21

⇒y=21−6

⇒y=15

Hence, the quantity of 90% pure acid is 6 liters and the quantity of 97% pure acid is 15 liters.