The Following Table Shows the Starting Salaries of a Sample

Short Answer

The following table shows the starting salaries of a sample of recent business graduates.
$$\begin{array} { c c } \text { Income In } \$1,000s & \text { Number af Graduate } \\15 - 19 & 40 \\20 - 24 & 60 \\25 - 29 & 80 \\30 - 34 & 18 \\35 - 39 & 2\end{array}$$
a. What percentage of graduates in the sample had starting salaries of at least $30,000?
b. Of the graduates in the sample, what percentage had starting salaries of less than $25,000?
c. Based on this sample, what percentage of all business graduates do you estimate to have starting salaries of at least $20,000?