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India play two matches each with West Indies and Australia. In any match the probabilities of India getting 0,1 and 2 points are 0.45,0.05 and 0.50 respectively. Assuming that the outcomes are independent, the probability of India getting at least 7 points is

Option: 1

0.0875


Option: 2

\frac{1}{16}


Option: 3

0.1125


Option: 4

None of these


Answers (1)

best_answer

\mathrm{P\left(E_0\right)=0.45, \quad P\left(E_1\right)=0.05, \quad P\left(E_2\right)=0.50}

For 7 points there should be at least three instances of 2 points and one of 1 or 2 points.

\therefore   the required probability

\begin{aligned} & \mathrm{=P\left(E_2 E_2 E_2 E_2\right)+P\left(E_2 E_2 E_2 E_1\right)+P\left(E_2 E_2 E_1 E_2\right)+P\left(E_2 E_1 E_2 E_2\right)+P\left(E_1 E_2 E_2 E_2\right)} \\ \\& = \mathrm{\left\{P\left(E_2\right)\right\}^4+4\left\{P\left(E_2\right)\right\}^3 \cdot P\left(E_1\right)} \\ \\& =(0.50)^4+4(0.50)^3 \cdot(0.05)=0.0875 . \end{aligned}

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shivangi.bhatnagar

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