please answer all of the following questions.

1. The volume of a sphere is increasing at a rate of 75. How fast is the radius increasing when the radius is 10 cm?

2. A ladder 5 ft long is leaning against a wall. The bottom of the ladder slides away from the wall at a rate of 0.5. How fast is the ladder sliding down the wall when the bottom of the ladder is 3 ft from the wall?

3. Car A is traveling west at 35 mph and car B is traveling north at 45 mph both heading toward the intersection. At what rate are the cars approaching each other when car A is 0.8 mi and car B is 0.6 mi from the intersection?

thank you