Mathematics - Probability Question with Solution | TestHub

MathematicsProbabilityConditional probabilityMedium2 minPYQ_2020
MathematicsMediumnumerical

Two fair dice, each with faces numbered1,2,3,4,5and6, are rolled together and the sum of the numbers on the faces is observed. This process is repeated till the sum is either a prime number or a perfect square. Suppose the sum turns out to be a perfect square before it turns out to be a prime number. Ifpis the probability that this perfect square is an odd number, then the value of14pis_____

Answer:
8.00
Solution:

Perfect Square can be 4 or 9, which can be obtained by 1,3,3,1,2,2,6,33,6,5,4,4,5.

Prime Number can be 2 or 3 or 5 or 7 or 11, which can be obtained by 

1,1,1,2,2,1,1,4,4,1,2,3,3,2,1,6,6,1,5,2,2,5,3,4,4,3,6,5,5,6

P(square or prime)=2236

P Perfect square is odd  perfect square before prime =436+1436.436+1436.1436.436+....736+1436.736+1436.1436.736+......

=4361-14367361-1436=47=P

14 P=8

Stream:JEE_ADVSubject:MathematicsTopic:ProbabilitySubtopic:Conditional probability
2mℹ️ Source: PYQ_2020

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