Question

you have boasted to your friends that you can ride your bicycle at 30 KPH (KM per Hour) over a 30KM race track comprising of two 15km laps. However, when you finish the first lap, your coach tells you that your average is only 15 KPH. How fast must you ride to bring your average speed to 30 kph.

Answer 1

faster than 100 kph

Step-by-step explanation:

Time taken to complete the first lap is

`\frac{15\ \text{km}}{15\ \text{kph}}=1\ \text{hour}`

If the person's average speed is to be 30 kph then the complete race would be over in
`(30)/(30)=1\ \text{hour}`

But 1 hour has passed in the first lap already so, the next 15 km must be covered in 0 time.

So, the speed of the bike must be more than 100 kph.