Pure acid is to be added to a 10% acid solution to obtain 90L of 81% solution. What amounts of each should be used? How many liters of 100% pure acid should be used to make the solution?

Step-by-step explanation:

let X be the quantity of 100% acid

let Y be the quantity of  10% acid

X + Y = 90

Y = 90 - X

         X(100) + Y(10) = 90(81)

X(100) + (90 - X)(10) = 90(81)

   100X + 900 - 10X = 7290

                         90X = 6390

                              X = 71 L

i can answer this question sweetie!

step-by-step explanation:

since your problem is x^4 = 81, what you have to undeo is the "to the fourth power" part.

the inverse (opposite operation) of "to the fourth power" is "to the fourth root".

  (x^4) ^ ¼   = 81 ^ ¼  

  81 = 3^4     so (3 ^ 4) ^ ¼   =   3 ^ 1   = 3

by hand: (3 ^ 4) ^ ¼   =   3 ^ (4 x ¼) = 3 ^ 1   = 3   (when you take a power to a power, multiply the exponents.)

or, do it by calculator. one way of finding the fourth root is to use ^ (1/4)

step-by-step explanation: