Let x represent the number of liters of 50% acid Theresa puts into the mix. The the number of liters of 30% acid will be (420-x). The total amount of acid in the final solution will be ...
0.50x + 0.30(420-x) = 0.45(420)
0.20x + 126 = 189 . . . . . . . . . . . . . . . simplify
0.20x = 63 . . . . . . . . . . . . . . . . . . . . . subtract 126
x = 63/0.20 = 315 . . . . . . . . . . . . . . . liters of 50% solution
(420-x) = 420-315 = 105 . . . . . . . . . liters of 30% solution
Theresa should mix ...
105 liters of 30% solution
315 liters of 50% solution
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Answer: B
Step-by-step explanation:
Symmetrical functions can be about the x and y axis. Essentially, if we reflect the graph across the y or x axis, we get the same graph. Some other graphs can be reflected across both the x and y axis at the same time and be symmetrical. These can be classified as odd and even functions. You can test this by replacing x and y with -x and -y and simplify the equation. If the results comes out to be the same as the original, it is symmetrical across the origin.
Best of Luck!