QJEEM21Mad821: JEE Main 2021 Mathematics - Class 12 JEEM21Mad821 Solution: Let 9 distinct balls be distributed among 4 boxes, B 1 , B 2 ,…

Question

Verified Solution • 2025–26 Session moderate

Let 9 distinct balls be distributed among 4 boxes, B₁, B₂, B₃ and B₄. If the probability than B₃ contains exactly 3 balls is

k {(\frac{3}{4})}^{9}

then k lies in the set :

Accepted Answer

Required probability =

\frac{^{9} C_{3} {.3}^{6}}{4^{9}}

= \frac{^{9} C_{3}}{27} . {(\frac{3}{4})}^{9}

= \frac{28}{9} . {(\frac{3}{4})}^{9} \Rightarrow k = \frac{28}{9}

Which satisfies

| x - 3 | < 1

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