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QJEEAdv22Ma74b9: JEE Advanced 2022 Mathematics - Class 12 JEEAdv22Ma74b9 Solution: Two players, and , play a game against each other. In every…
Two players, and , play a game against each other. In every round of the game, each player rolls a fair die once, where the six faces of the die have six distinct numbers. Let and denote the readings on the die rolled by and , respectively. If x>y , then scores 5 points and scores 0 point. If , then each player scores 2 points. If x < y , then scores 0 point and scores 5 points. Let and be the total scores of and , respectively, after playing the round.
| List-I | List-II |
|---|---|
| (I) Probability of is | (P) |
| (II) Probability of \left(X_{2}>Y_{2}\right) is | (Q) |
| (III) Probability of is | (R) |
| (IV) Probability of \left(X_{3}>Y_{3}\right) is | (S) |
| (T) |
The correct option is:
Multiple Choice Options
- A (I) (Q); (II) (R); (III) (T); (IV)
- B (I) (Q); (II) (R); (III) (T); (IV) (T)
- C (I) (P); (II) (R); (III)
- D (I) (P); (II) (R); (III) (Q); (IV) (T)
Step-by-Step Verified Solution
Given,
Now finding the probability of all we get.
\begin{aligned}& \mathrm{P}\left(\mathrm{X}_2>\mathrm{Y}_2\right)=\mathrm{P}(10,0)+\mathrm{P}(7,2) \\\\& =\frac{5}{12} \times \frac{5}{12}+\frac{5}{12} \times \frac{1}{6} \times 2 \\\\& =\frac{45}{144}=\frac{5}{16} \rightarrow \mathrm{R} \\\\& \mathrm{P}\left(\mathrm{X}_2=\mathrm{Y}_2\right)=\mathrm{P}(5,5)+\mathrm{P}(4,4) \\\\& =\frac{5}{12} \times \frac{5}{12} \times 2+\frac{1}{6} \times \frac{1}{6} \\\\& =\frac{25+2}{72}=\frac{3}{8} \\\\& \mathrm{P}\left(\mathrm{X}_3=\mathrm{Y}_3\right)=\mathrm{P}(6,6)+\mathrm{P}(7,7) \\\\& =\frac{1}{6 \times 6 \times 6}+\frac{5}{12} \times \frac{1}{6} \times \frac{5}{12} \times \frac{1}{6} \\\\& =\frac{77}{432} \rightarrow \mathrm{F} \\\\& \mathrm{P}\left(\mathrm{X}_3>\mathrm{Y}_3\right)=\frac{1}{2}\left(1-\frac{77}{432}\right)=\frac{355}{864} \rightarrow \mathrm{S} \\\\& P\left(X_2 \geq Y_2\right)=\frac{5}{16}+\frac{3}{8}=\frac{11}{16} \rightarrow \mathrm{Q}\end{aligned}
Now finding the probability of all we get.
\begin{aligned}& \mathrm{P}\left(\mathrm{X}_2>\mathrm{Y}_2\right)=\mathrm{P}(10,0)+\mathrm{P}(7,2) \\\\& =\frac{5}{12} \times \frac{5}{12}+\frac{5}{12} \times \frac{1}{6} \times 2 \\\\& =\frac{45}{144}=\frac{5}{16} \rightarrow \mathrm{R} \\\\& \mathrm{P}\left(\mathrm{X}_2=\mathrm{Y}_2\right)=\mathrm{P}(5,5)+\mathrm{P}(4,4) \\\\& =\frac{5}{12} \times \frac{5}{12} \times 2+\frac{1}{6} \times \frac{1}{6} \\\\& =\frac{25+2}{72}=\frac{3}{8} \\\\& \mathrm{P}\left(\mathrm{X}_3=\mathrm{Y}_3\right)=\mathrm{P}(6,6)+\mathrm{P}(7,7) \\\\& =\frac{1}{6 \times 6 \times 6}+\frac{5}{12} \times \frac{1}{6} \times \frac{5}{12} \times \frac{1}{6} \\\\& =\frac{77}{432} \rightarrow \mathrm{F} \\\\& \mathrm{P}\left(\mathrm{X}_3>\mathrm{Y}_3\right)=\frac{1}{2}\left(1-\frac{77}{432}\right)=\frac{355}{864} \rightarrow \mathrm{S} \\\\& P\left(X_2 \geq Y_2\right)=\frac{5}{16}+\frac{3}{8}=\frac{11}{16} \rightarrow \mathrm{Q}\end{aligned}