How many liters each of a 30% acid solution and a 50 % acid solution must be used to produce 70 liters of a 40 % acid solution? (Round to two decimal places if necessary.)

  30%: 35 liters

  50%: 35 liters

Step-by-step explanation:

The desired concentration is halfway between the concentrations of available solutions, so the mixture will be equal amounts of each.

  35 liters of 30% acid and 35 liters of 50% acid must be used

If you want to write an equation, it usually works well to let the variable represent the amount of the most concentrated constituent: 50% acid. Then the amount of acid in the final mix is ...

  0.50x +0.30(70 -x) = 0.40(70)

  0.20x +21 = 28 . . . . simplify

  0.20x = 7 . . . . . . . . . subtract 21; next, divide by 0.20

  x = 35 . . . . . . amount of 50% solution (liters)

  70-x = 35 . . . amount of 30% solution (liters)

answer set (b) 0.5, 3/4 80% is in order from least to greatest.  

step-by-step explanation:

in order to compare rational numbers to each other, it is much easier if they are in the same form.   typically, the best form in which to evaluate rational numbers is in decimals.   in order to convert a percent to a decimal, you would divide the given percentage by 100.   you can also accomplish the conversion by moving the decimal point over two places to the left.   for example, the decimal value of 80% is 80/100, or 0.8.   in order to convert a fraction to a decimal, you need to divide the numerator by the denominator.   for example, 3/4 is 0.75.   so, for choice (b) 0.5 3/4 (0.75), 80% (0.8) is the only choice in which the numbers are in order from least to greatest.  

idk i would have to be there to under stand it

step-by-step explanation:

idk i would have to be there to under stand it