Below given is a text from Our president message which is given in students journal of December, 2010 :

Changes in CPT :-

Common Proficiency Test: The Council at its 300th meeting reviewed the requirement for passing the Common Proficiency Test and decided that a candidate shall have to obtain at one sitting, a minimum of 30 per cent marks (out of maximum marks specified by the Council for each Section) and a minimum of 50 per cent marks in the aggregate of all the Sections, subject to the principle of negative marking, in a manner as may be specified by the Council from time to time subject to proposed amendments in the regulations approved by the Central Government.

U Can read the whole text at 

https://www.icai.org/new_post.html?post_id=6530