Question

8. Jess walked for 45 minutes at 3 km/h and then ran for half an hour at x km/h. At the end

Answer 1

Answer:

x = 7.5 km/h

Step-by-step explanation:

• First calculate the distance covered by walking at 3 km/h for 45 minutes ( 0.75 h):

distance = speed × time

              = 3 × 0.75

              = 2.25 km

• Therefore, she covered 2.25 km of the total journey by walking. Since she was 6 km from the starting point at the end of the entire journey, we can calculate the distance remaining, which she had to run:

distance she had to run = 6 - 2.25

                                        = 3.75 km

• Now we can calculate the speed of the 30 minute (0.5 h) run:

speed = distance ÷ time

           = 3.75 ÷ 0.5

           = 7.5 km/h    

This means that she ran at 7.5 km/h for half an hour.

∴ x = 7.5