1. Suppose a runner takes 45 min to run a route at 8mi/h at the beginning of training season. By the end of training season she can run the same route in 38 min. What is her speed at the end of training season?
2. the distance between Atlanta, Georgia, and Albuquerque, New Mexico, is about 1270 mi. The groundspeed for jet traffic from Albuquerque to Atlanta can be about 18% faster than the groundspeed from Atlanta to Albuquerque. Let R be the speed from Atlanta to Albuquerque in miles per hour. What is a simplified expression for the round-trip flying time?

Question

1. Suppose a runner takes 45 min to run a route at 8mi/h at the beginning of training season. By the end of training season she can run the same route in 38 min. What is her speed at the end of training season? 
2. the distance between Atlanta, Georgia, and Albuquerque, New Mexico, is about 1270 mi. The groundspeed for jet traffic from Albuquerque to Atlanta can be about 18% faster than the groundspeed from Atlanta to Albuquerque. Let R be the speed from Atlanta to Albuquerque in miles per hour. What is a simplified expression for the round-trip flying time?

anonymous · Answer

3. For a 225-watt bulb, the intensity I of light in lumens at a distance of x feet is I = 225/x^2. 
A. What is the intensity of light 5 ft from the bulb?

B. Suppose your distance from the bulb doubles. How does the intensity of light change? Explain.