There are a number of books on a shelf. If one book is the 6th from the left and 4th from the right, how many books are on the shelf?

NATIONAL GEOGRAPHIC

Urut berdasarkan

National Geographic Indonesia 2015-02 Februari Rp 20.000	National Geographic Indonesia 2013-03 Maret Rp 15.000	National Geographic Indonesia 2013-02 Februari Rp 15.000	National Geographic Indonesia 2012-12 Desember Rp 15.000

Beli	Beli	Beli	Beli
National Geographic Indonesia 2012-11 November Rp 15.000	National Geographic Indonesia 2012-10 Oktober Rp 15.000	National Geographic Indonesia 2012-09 September Rp 15.000	National Geographic Indonesia 2012-08 Agustus Rp 15.000

Beli	Beli	Beli	Beli
National Geographic Indonesia 2012-03 Maret Rp 15.000	National Geographic Indonesia 2012-02 Februari Rp 15.000	National Geographic Indonesia 2012-01 Januari Rp 15.000

Beli	Beli	Beli