Class 9

Mathematics 

Dated: 27/8/2020                                                                      Due Date: 30/8/2020

Topic:  Probability

Q1) A box contains 50 bolts and 150 nuts. On checking the box, it was found that half of the bolts and half of the nuts are rusted. If one item is chosen at random, find the probability that it is rusted. 

Q2) A dice is rolled several times and its outcomes are recorded as below :

Q3) If P (event E) = 0.47, then find P(not E).

Q4) The probability of guessing the correct answer to a certain question is x/ 2.If probability of not guessing the correct answer is 2 /3 then find x.

Q5) In a throw of a die, find the probability of not getting 4 or 5.

Q6) In a class, there are x girls and y boys, a student is selected at random, then find the probability of selecting a boy.

Q7) If the probability of winning a race of an athlete is 1 / 6 less than twice the probability of losing the race. Find the probability of winning the race. 

Q8) Two coins are tossed simultaneously for 360 times. The number of times ‘2 Tails’ appeared was three times ‘No Tail’ appeared and number of times ‘1 tail’ appeared is double the number of times ‘No Tail’ appeared. Find the probability of getting ‘Two tails’.

 Q9) A die was rolled 100 times and the number of times, 6 came up was noted. If the experimental probability calculated from this information is 2 /5 then how many times 6 came up? 

 Q10) An insurance company selected 2000 drivers at random (i.e., without any preference of one driver over another) in a particular city to find a relationship between age and accidents. The data obtained are given in the following table :

Q11) Find the probability of the following events for a driver-selected at random from the city:

(i) being 18-29 years of age and having exactly 3 accidents in one year.
(ii) being 30-50 years of age and having one or more accidents in a year.
(iii) having no accident in one year.

Solve Ex 12.1 of Ncert Textbook