The length of time it takes students to complete a statistics examination is uniformly distributed and varies between 40 and 60 minutes. What is the probability that a student will take no more than 45 minutes to complete the examination?

The area of a rectangle is 10 cm^2. one side of the rectangle is x cm. express the perimeter of the rectangle in terms of x and show that this rectangle cannot have a perimeter of 12 cm. the perimeter of the rectangle in terms of x is __ cm