Answer:
a) Figure attached
b) For this case we want this probability:

And we can use the complement rule:

And we can use the cumulative distribution function given by:

And replacing we got:

Step-by-step explanation:
For this case we define the random variable X= depth (in centimeters) of the bioturbation layer in sediment for a certain region, and we know the distribution for X, given by:

Part a
For this case we can see the figure attached.
Part b
For this case we want this probability:

And we can use the complement rule:

And we can use the cumulative distribution function given by:

And replacing we got:
