Answer:
32 mmol/L
Explanation:
Assume you have the following table:
[tex]\begin{array}{cc}\textbf{c/mmol$\cdot$L$^{\mathbf{-1}}$} &\textbf{rate/\% of max}\\30 & 45 \\40 & 65 \\\end{array}[/tex]
Assume the relationship is linear in this concentration range.
The difference between 45 and 65 is 20.
The difference between 45 and 50 is 5.
So, 50 is 5/20 = ¼ the interval.
The corresponding concentration interval should be
¼(40 - 30) = ¼ × 10 =2.5
The concentration corresponding to 50 % of maximum rate is
(30 + 2.5) mmol/L = 32 mmol/L
