Last Monday We Hired a Typist to Work from 8am

Short Answer

Last Monday we hired a typist to work from 8am to 12 noon.His typing speed decreased between 8am and his 10am cup of coffee, and increased again afterwards, between 10am and noon.His instantaneous speed (measured in characters per second)was measured each hour and the results are given below:
$\begin{array}{lccccc}\text { Time } & 8 \text { am } & 9 \text { am } & 10 \text { am } & 11 \text { am } & 12 \text { noon } \\\text { Speed } & 6 & 4 & 1 & 3 & 5\end{array}$ You want to estimate the total number of characters typed between 8am and 12 noon.Find an upper estimate using Reimann sums.