|[http://www.ncert.nic.in/ncerts/textbook/textbook.htm?iemh1=15-15 NCERT Textbook Class - IX - Mathematics - Chapter - 15 - Probability] | |[http://www.ncert.nic.in/ncerts/textbook/textbook.htm?iemh1=15-15 NCERT Textbook Class - IX - Mathematics - Chapter - 15 - Probability] |