Question

Hook and Neil are racing. Hook runs 12 kilometers with an average speed of 14.88 kph. Neil runs the same distance but is 4 minutes slower than Hook. What is Neil's average speed in kilometers per hour?

Answer 1

Neil's average speed is 13.74 km/h

Explanation:

- Hook runs 12 kilometers

- His average speed is 14.88 km/h

∵ Average speed = total distance ÷ total time

∴ Total time = total distance ÷ average speed

∵ His average speed = 14.88 km/h

∵ His distance = 12 km

∴ His time = 12 ÷ 14.88 =
`(25)/(31)` hour

- Neil runs the same distance

- His time longer than the time of Hook by 4 minutes because

he slower than him by 4 minutes

- Lets change the 4 minutes to hour

∵ 1 hour = 60 minutes

∴ 4 minutes =
`4*(1)/(60)` =
`(1)/(15)` hour

∵ The time of Hook
`(25)/(31)` hour

∵ The time of Neil is longer by
`(1)/(15)` hour

- Add the value above to the time of Hook to get the time of Neil

∴ The time of Nile =
`(25)/(31)` +
`(1)/(15)`

∴ The time of Nile =
`(406)/(465)` hours

* Now lets find the average speed of Neil

∵ The distance of Neil is 12 km

∵ His time =
`(406)/(465)` hours

∴ His average speed = 12 ÷
`(406)/(465)` = 13.74 km/h

* Neil's average speed is 13.74 km/h