1. Linear Applications Wednesday, November 13, 2013

2. Bathtub Problem You pull out the plug from the bathtub. After 40 seconds, there are 13 gallons of water left in the tub. One minute after you pull the plug, there are 10 gallons left. Assume a constant rate for the amount of gallons that drain each second.

3. Step 1: Define Variables

4. Step 2: Find the Slope

5. Step 3: Use Point-Slope to Write the Equation

6. How many gallons after 20 seconds? After 50 seconds?

7. At what time will there be 7 gallons left in the tub?

8. Find the y-intercept. What does it mean?

9. Find the x-intercept (time- intercept). What does it mean?

10. You drive home from a football game. Assume that the distance varies linearly with time. Suppose you are 11km from home when you have been driving 10 minutes, and 8 km away from home when you drove for 15 minutes. Find an equation to represent this scenario.

11. Define the Variables

12. Find the slope

14. Predict your distance from home after driving 20 min, 25 min, and 30 min. D(20) = 5km D(25) = 2km D(30) = -1

15. When were you 7 km from home? How many minutes have you been traveling

16. Find the distance-intercept. What does this number represent in the real world? 17km This is the number of miles you are away from home when you start your journey.

17. Find the time-intercept. What does this number represent in the real world?