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GATE | Sudo GATE 2020 Mock III (24 January 2019) | Question 62

  • Last Updated : 23 Jan, 2020

Roll a die. If the side that comes up is odd, you win the $ equivalent of that side. If it is even, you lose $4.

You expected earnings is __________ .
(A) -1/2
(B) -1
(C) 1
(D) 1/2


Answer: (A)

Explanation: Let X = your earnings,

X=1 P(X=1) = P({1}) = 1/6
X=3 P(X=1) = P({3}) = 1/6
X=5 P(X=1) = P({5}) = 1/6
X=-4 P(X=1) = P({2,4,6}) = 3/6 

Therefore,

E(X) 
= 1*1/6 + 3*1/6 + 5*1/6 + (-4)*1/2 
= 1/6 + 3/6 +5/6 – 2
= -1/2 

Option (A) is correct.

Quiz of this Question

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