# why do we multiply 5/18 or 18/5 when we convert?

Kindly refer to the answer given by Rohan.
@ Rohan, keep posting.

To convert km/hr into m/sec :.
Let we have to convert x km/hr to m/s
since, we know 1 km = 1000 m and 1 hr = 3600 s
So, x km/hr =

• 30

see, when you want to convert km into m what do you do ? you multiply the number which is in km with 1000

and when you want to convert hr into sec you multiply it with 3600 . so when you want to convert km/hr into m/sec you need to multiply the number in km/hr with 1000/3600  and when you simplify 1000/3600 you get 5/18 .so to convert km/hr to m/sec you need to multiply it with 5/18.and to convert it back to km/hr it is the inverse ,you need to multiply the number in km/sec with 18/5

• 10

sorry the last sentence is wrong.it is -and to convert it back to km/hr you need to multiply the number in m/sec with 18/5

• 4

Let any vehicles speed be 1m/s.

To convert m/s into km/hr

We know that 1m=1/1000km

1s=1/60*60 hr

So, 1m/s into km/hr=1*60*60/1000

If We cancel these terms than we get 18/5.

• 9
What are you looking for?