Q20 of 47 Page 1

In a single throw of a pair of different dice, what is the probability of getting (i) a prime number on each dice? (ii) a total of 9 or 11?

Two dice can be thrown in 6 × 6

= 36 ways


(i) Now a prime number on each dice can be obtained as follows:


(2, 2), (2, 3), (2, 5), (3, 2), (3, 3), (3, 5), (5, 2), (5, 3), (5, 5) = 9 ways


∴



(ii) Also total of 9 or 11 can be obtained as follows:


(3, 6), (6, 3), (4, 5), (5, 4), (5, 6), (6, 5) = 6 ways




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