Mathematics · Probability

JEE Advanced 2023 — Paper 2 — Question 38

Consider the 6×66 \times 6 square in the figure. Let A1,A2,…..,A49A_{1}, A_{2}, \ldots . ., A_{49} be the points of intersections (dots in the picture) in some order. We say that AiA_{\mathrm{i}} and AjA_{\mathrm{j}} are friends if they are adjacent along a row or along a column. Assume that each point AiA_{\mathrm{i}} has an equal chance of being chosen.

Two distinct points are chosen randomly out of the points A1, A2,…..,A49\mathrm{A}_{1}, \mathrm{~A}_{2}, \ldots . ., \mathrm{A}_{49}. Let pp be the probability that they are friends. Then the value of 7p7 p is

Answer: 0.5

Numerical answer — enter this value.

Step-by-step solution

2 Consecutive points can be chosen in 2×6×72 \times 6 \times 7 ways =84=84 ways So, n(E)=84;n(S)=49C2n(E)=84 ; n(S)={ }^{49} C_{2} So, 7p=7×8449C2=0.57 \mathrm{p}=7 \times \frac{84}{{ }^{49} \mathrm{C}_{2}}=0.5

Answer key and solution verified before publishing.

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Exam
JEE Advanced 2023
Paper
Paper 2
Subject
Mathematics
Chapter
Probability
Topic
Total Probability and Baye's Theorem
Consider the 6 × 6 square in the figure. Let A 1 , A 2 , ldots . ., A… | JEE Advanced 2023 PYQ with Solution · DhiX AI