Question

A beaker contains 400 milliliters of a solution that is 80% acid. How many milliliters of a 50% acid solution should be added to obtain a solution that is 75% acid?

Answer 1

Answer:

80 ml of  50% acid solution should be added to obtain a solution that is 75% acid.

Step-by-step explanation:

A beaker contains 400 milliliters of a solution that is 80% acid

Acid = (80/100) * 400 = 320 ml

let say  2x  ml of 50% acid  solution is added

then acid in solution = (50/100)2x = x ml

Total acid = 320 + x ml

Total solution = 400 + 2x  ml

320 + x  = (75/100)(400 + 2x)

=> 320 + x  = (3/4)(400 + 2x)

=> 320 + x  = (3/2)(200 + x)

=> 640 + 2x = 600 + 3x

=> x = 40

2x = 80

80 ml of  50% acid solution should be added to obtain a solution that is 75% acid.

Answer 2

Given :

A beaker contains 400 milliliters of a solution that is 80% acid.

To Find :

Dilution of 400 ml of solution that is 80% acid with the solution of 50% acid such that the resulting solution will become 75% acid solution.

Solution :

A beaker contains 400 milliliters of a solution that is 80% acid.

Dilute that with the solution of 50% acid and make it 75% acid solution.

Let the used amount of 50% acid solution represents by 'x'

The equation will be,

$(400)(\frac{80}{100})+(x)(\frac{50}{100})=(\frac{75}{100})(400+x)$

(400)(0.80) + (x)(0.50) = (0.75)(400 + x)

320 + 0.5x = 300 + 0.75x

-0.25x + 320 = 300

-0.25x = -0.20

x = 80

80 milliliters of a 50% acid solution should be added to obtain a solution that is 75% acid.