Please I'm stuck!!!!!

A person is driving a car on a straight road. The graph shows the distance in y miles that the individual is from home after x hours.

the graph has the following points
(1, 40) and (3, 90)

Find the slope intercept of the line
y = ____x + ______

How fast is the car traveling?
_______ Miles per hour.
(Type and integer or decimal)

How far was the individual from home initally?

________ miles
(Type and integer or decimal)

How far was the individual from home after 3 hours and 15 minutes?
_________ miles
(Type in integer or decimal)

I am unsure how to solve the last couple of parts to this problem.
Help!!!