Hello. These are practice questions from the internet. Can you please help me with them? The answers are already provided. I just need an explanation. Please provide an explanation for the answers so that I can understand, and please don't use cursive as I can't read that.

18. Car A is travelling west at 50 mi/h and car B is travelling north at 60 mi/h. Both are headed for the intersection of the two roads. At what rate are the cars approaching each other when car A is 0.3 mi and car B is 0.4 mi from the intersection? Answer: 78 mi/h. 19. A kite 100ft above the ground moves horizontally at a speed of 8 ft/s. At what rate is the angle between the string and the horizontal decreasing when 200 ft of string has been let out? Answer: 0.02 rad/s 20. A rectangular storage container with an open top is to have a volume of 10m. The length of its base is twice the width. Material for the base costs $10 per square meter. Material for the sides costs $6 per square meter. Find the cost of materials for the cheapest such container. Answer: $163.5413. Find the absolute maximum and absolute minimum values of f(x) = e2x - 10x + 1, on the interval [0, 2]. Answer: The absolute minimum value is f((In 5)/2) = -2.047 and the absolute maximum value is f(2) = 35.598