I'm using iPhone with iOS7?

Can i close multiple Apps at a time in my iphone?

No i don't think so but maybe Apple will do something this

Yes double click the home button then the apps will come up and flick them away by flicking upwards

Yes it can be possible to close the multiple by double clicking the home page.
for more information about ios iphone visit the following link
http://freeinfozone.com/apple-ios-7-with-new-user-interface-and-new-features-available/#&panel1-3