Question

IS Uil Uice U De The
A pair of dice is tossed simultaneously. Find
the probability that the sum of numbers on
the dice is a prime number.

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Answer 1

u have to write all the 36 possibilities and choose among them the pairs which gives sum as a prime no.

possibilities are

(1,1),(1,2),(1,3),(1,4),(1,5),(1,6)

(2,1),(2,2),(2,3),(2,4),(2,5),(2,6)

(3,1),(3,2),(3,3),(3,4),(3,5),(3,6)

(4,1),(4,2),(4,3),(4,4),(4,5),(4,6)

(5,1),(5,2),(5,3),(5,4),(5,5),(5,6)

(6,1),(6,2),(6,3),(6,4),(6,5),(6,6)

we know the sum starts from 2 and goes to 12

so in this we hve five prime no.s i.e. 2,3,5,7,11

count those pairs giving sum above five primes and divide by total 36 possibilities

ans will be 15/36