I walked for 2 1/2 hours at 4km/h and for 4 hours at 2 1/2 km/h. What was the average speed for the entire journey?

Average speed of the entire journey is 3.08 km/hr

Step-by-step explanation:

Step 1: In the first half, given that the speed = 4 km/h and time = 2 1/2 = 2.5 hrs. Calculate the distance covered.

Distance = Speed × Time = 4 × 2.5 = 10 km

Step 2: In the second half, given that speed = 2 1/2 = 2.5 km/hr and time = 4 hrs. Calculate the distance covered.

Distance = 2.5 × 4 = 10 km

Step 3: Calculate average speed.

Average Speed = Total distance/Total time

                          = 10 + 10/2.5 + 4 = 20/6.5

                          = 3.08 km/hr

She would multiply the rate by the years to find the average rise in water levels, or 1.8 times 6.2 = 11.16. To find the difference between the water levels, she would subtract -13.64 from 11.16.

Step-by-step explanation: