Use the rational function y= (100)(0.02)+x(0.005)100+x and a calculator.
900 mL
Practice makes perfect
We will use the rational function below.
y=(100)(0.02)+x(0.005)/100+x
We want to find for which value of x this function is equal to 0.65 %= 0.0065. To do so, we will first draw the graph of y_1 and y_2 on a calculator, then use the intersect option.
y_1=& (100)(0.2)+x(0.005)/100+x
y_2= & 0.0065
To enter the equations on our calculator, press the Y= button and write them in the two first rows.
The calculator will draw the equations after pushing GRAPH. For the functions to be visible on the screen, we have to re-size the standard window by pushing the WINDOW button. We will change the settings to a more appropriate size and then push GRAPH.
To find point of intersection, we can use the intersect option, which we get by pushing 2nd and TRACE. We select both graphs and provide the calculator with a guess as to where the intersection might be.
The functions intersect at the point ( 900, 0.0065). Therefore, we should add 900 mL of the 0.5 % solution to get a 0.65 % solution.
