Misty wishes to obtain 85 ounces of a 40% acid solution by combining a 72% acid solution with a 25% acid solution. How much of each solution should Misty use?

13.15 ounces of 72% acid and 71.85 ounces of 25% acid are needed

Step-by-step explanation:

Total mass of acid required= 85 ounces

Let the mass of 72% acid be 'a'

Let the mass of 25% acid be 'b'

a + b = 85

b = 85-a

85(40/100) = a(72/100) + b(25/100)

85(2/5) = a(72/100) +(85- a) (25/100)

34 = (72a/100) + (2125/100) - (25a/100)

34 - (2125/100) = (72a + 25a) /100

(3400-2125)/100 = 97a /100

97a = 1275

a =  13.15 ounces

b = 85 - 13.14

b = 71.85 ounces

13.15 ounces of 72% acid and 71.85 ounces of 25% acid are needed

3 is greater then both of those numbers