Access Answers of Maths NCERT class 10 Chapter 15 – Probability Class 10 Maths Chapter 15 Exercise: 15.1 (Page No: 308) 1. Complete the following statements: (i) Probability of an event E + Probability of the event ‘not E’ = ___________ . (ii) The probability of an event that cannot happen is __________. Such an event is called ________ . (iii) The probability of an event that is certain to happen is _________ . Such an event is called _________ . (iv) The sum of the probabilities of all the elementary events of an experiment is __________ . (v) The probability of an event is greater than or equal to and less than or equal to __________. Solution: (i) Probability of an event E + Probability of the event ‘not E’ =  1 . (ii) The probability of an event that cannot happen is  0 . Such an event is called  an impossible event . (iii) The probability of an event that is certain to happen is  1 . Such an event is called  a sure or certain event . (iv) The sum of t