Word order: Whis is your pen? vs Which pen is yours?

[Jaghal]

Hello!

This is my first post in the forum and I hope it won't be the last
I was reading in a book when I face the following:

It says what's the difference between the following sentences:

1- Whis is your pen?
2-Which pen is yours?

AND

3- Whose car is that?
4- Whose is that car?

Can you help me please and explain the case to me.

Thanks is advance

[Mister Micawber]

Welcome to English-test.net, Jaqhal.

They are just two ways of asking the same questions.
_________________
Native English teacher at Mister Micawber's