B) Find the median queuing time
please help

11 minutes.

Step-by-step explanation:

To find the median queing time from the cumulative frequency curve, we find

and trace it on the cumulative frequency curve.

From the graph, that total frequency is 100.

Half of this 50.

We trace the 50th item.

First locate 50 on the vertical axis and trace to the horizontal axis.

This corresponds to 11.

Note that each box is 0.5 units on the queing time axis.

i hope this is what you were looking for.

see attached graph