which is the correct sentence?
Mr. Parkash leads a very busy life so he goes everywhere by a scooter.
Mr. Parkash leads a very busy life so he goes everywhere on a scooter.
which is the correct sentence?
Mr. Parkash leads a very busy life so he goes everywhere by a scooter.
Mr. Parkash leads a very busy life so he goes everywhere on a scooter.
If you drop the article "a" from your sentence using "by", you have two idiomatic ways of essentially saying the same thing:
Mr. Parkash leads a very busy life so he goes everywhere by scooter.
Mr. Parkash leads a very busy life so he goes everywhere on a scooter.
Both are correct. By car, by train, by plane, by boat etc are all idiomatic ways of describing the mode or transport. You can also say by air, by sea, by road etc which does not specify the type of vehicle but broadly describes the mode of travel.
When you specificy the vehicle, you have to use the appropriate preposition. For example, you would say in a car, but on a bike or scooter (because you sit atop them).