Q20 of 31 Page 308

Suppose you drop a die at random on the rectangular region shown in Fig. 15.6. What is the probability that it will land inside the circle with diameter 1m?

Area of rectangle = l × b = 3 × 2 = 6 m2

Area of circle (of diameter 1 m) = r2


= π * ()2


=


P (die will land inside the circle)


=


=


=


More from this chapter

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18

A box contains 90 discs which are numbered from 1 to 90. If one disc is drawn at random from the box, find the probability that it bears

(i) A two-digit number


(ii) A perfect square number


(iii) A number divisible by 5

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A child has a die whose six faces show the letters as given below:


The die is thrown once. What is the probability of getting (i) A? (ii) D?

 21

A lot consists of 144 ball pens of which 20 are defective and the others are good. Nuri will buy a pen if it is good, but will not buy if it is defective. The shopkeeper draws one pen at random and gives it to her. What is the probability that

(i) She will buy it?


(ii) She will not buy it?

 22

Refer to Example 13. (i) Complete the following table:































Event : ‘Sum on 2 dice’



2



3



4



5



6



7



8



9



10



11



12



Probability



1/36








5/36






1/36



(ii) A student argues that ‘there are 11 possible outcomes 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 and12. Therefore, each of them has a probabilityDo you agree with this argument? Justify your answer