Answer
$99.95$
Work Step by Step
The interval $[a,b]$ is subdivided into $n$ intervals, and the function
$f(x)$ is a continuous function over $[a,b]$.
Here, Left Riemann sum $=\displaystyle \sum_{k=0}^{n-1}f(x_{k})\Delta x$
$=[f(x_{0})+f(x_{1})+\cdots+f(x_{n-1})]\Delta x$
where $a=x_{0} < x_{1} < \cdots < x_{n}=b$ are the endpoints of the subdivisions and $\displaystyle \Delta x=\frac{b-a}{n}$
We are given that $\text{cost}; C'(x)=20-\dfrac{x}{200}$ and $n=5$
$\displaystyle \Delta x=\frac{5-0}{5}=1$ with interval $[0, 5]$
Therefore, $\int_0^5 c'(x) \ dx=[c'(0)+c'(1)+c'(2)+c'(3)+c'(4)] \times 1\\=(20+19.995+19.99+19.985+19.98) \times 1 \\=99.95$
