# You run 100 meters in 15 seconds, 400 meters in 1 minute, and 800 meters in 2 minutes. How long will it take you to run 1 kilometer if you continue running at the same speed? (Hint: 1 kilometer...

You run 100 meters in 15 seconds, 400 meters in 1 minute, and 800 meters in 2 minutes.

How long will it take you to run 1 kilometer if you continue running at the same speed? (Hint: 1 kilometer equals 1000 meters)

### 7 Answers | Add Yours

The rate this individual is running is 100m per 15 seconds (distance/time). So, in order to run 1,000m, or 1 kilometer, it would take 150 seconds (15seconds x 10). 150 seconds is equal to **2.5 minutes** (150 seconds divided by 60 seconds).

The time taken to run 100 m is 15 seconds. To run 400 m the person needs 1 minute which is 4*15 = 60 s. To run 800 m, 1*2 = 2 minutes is required.

In all the three cases the speed of the person does not change; it is constant at 400/60 = 20/3 m/s.

The time required to run 1 km is `1000/(20/3)` = 150 seconds.

100/15 = 1000/x

15,000 = 100x

x = 150 seconds = 2.5 minutes.

For this problem, all you need to do is set up a ratio and cross multiply. You know that the average time is 100 meter for 15 seconds and that 1000 meters takes x amount of seconds.

100/15 = 1000/x

1000(15) = 100x

15,000 = 100x

x = 150 seconds

150 seconds would be equivalent to 2.5 minutes.

15 seconds = 100m

You know that 1km equals 1000m

so, 15*10 seconds= 1000m

150 seconds = 1000 metres

Change the seconds to minutes, which is 150/60=** 2.5 minutes**

I will take 2.5 min to run 1km (1000m) if continuing at same speed of 400m/min

it requires 2 minutes to complete 800 m. then an another 30 seconds to finish off 200 m. so 2 min 30 seconds will be required to finish off 1km.