Question

A car travels 25 metres a second. Find its speed in km/h.

Answer 1

Explanation:

One minute is equal to 60 seconds modeled by the ratio 1:60 one hour is equal to 60 minutes modeled by the ratio 1:60 therefore using substitution 1hour:60minutes(1):60seconds(60) therefore 1:
`60^(2)` or 3,600 so in this instance 25m/s = 25:1 and because a km is equal to 1,000 meters as denoted by the prefix kilo. One can understand that multiplying by 1,000 is the same as dividing by 1,000 less therefore instead of doing (25*3600)/1000 you can simply do 25*3.6 which yields 90.

Therefore 2.5m/s = 90km/h

PS. For future reference, you can reference a free conversion tool if you find that easier to use.

Answer 2

90 km/h

Explanation:

There are 3600 seconds in an hour. So, let's multiply the unit rate by 3600.

`3600*25=90000`

So, after 3600 seconds (or an hour), the car will have traveled 90000 meters.

Or, the car's rate is 90000 meters per hour.

1 meter is 0.001 kilometer. Let's multiply 90000 by 0.001 to find how many kilometers the car travels after an hour.

`90000*0.001=90`

So, the car's speed is 90 km/h.