Let 2P(a prime number)=1P(a composite number)=3P(1)=k
So, P(a prime number)=2k,
P (a composite number)=k,
and P(1)=3k
i.e. 6k+2k+3k=1
⇒k=111
P(success)=P(1or4)=3k+k=114
Number of trials, n=2
∴ required mean=np=2×114=118
A six faced die is biased such that 3×P(a prime number)=6×P(a composite number)=2×P(1). Let X be a random variable that counts the number of times one gets a perfect square on some throws of this die. If the die is thrown twice, then the mean of X is
Held on 27 Jul 2022 · Verified 6 Jul 2026.
113
115
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118
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