Answer:
make all the numbers have the same denominator, then simply see what multiplies to equal both fractions. your answer should be -3/10(1/5k+1)
Step-by-step explanation:
We are trying to find miles/hour, which shows that we are going to be dividing the total number of miles by the total number of hours. Thus, in this case, the miles/hour rate will be:

He drove 40 miles in one hour.
Do you need the area of the floor plan? If so here you go:
6*4 = 24, so 24 cm.
If y what? I think you're missing part of the question...
I believe this is how that exponential function would look as a graph (if you need a better pic let me know)