Two of the five mechanical engineers employed by the county sanitation department

Two of the five mechanical engineers employed by the county sanitation department have experience in the design of steam turbine power plants. You have been instructed to choose randomly two of the five engineers to work on a project for a new power plant.
a. What is the probability that you will choose the two engineers with experience in the design of steam turbine power plants?
b. What is the probability that you will choose at least one of the engineers with such experience?