X-and-Y-stand-in-a-line-at-random-with-10-other-peoples-What-is-the-probability-that-there-will-be-exactly-4-persons-between-X-and-Y-

Question Number 138960 by Dwaipayan Shikari last updated on 20/Apr/21

X a n d Y s t a n d i n a l i n e, a t r a n d o m w i t h 10 o t h e r p e o p l e s .

W h a t i s t h e p r o b a b i l i t y t h a t t h e r e w i l l b e e x a c t l y 4 p e r s o n s

b e t w e e n X a n d Y ?

Commented by mr W last updated on 20/Apr/21

p = \frac{2 \times C_{4}^{10} \times 4! \times 7!}{12!} = \frac{2 \times 25401600}{12!} = \frac{7}{66}

Commented by mr W last updated on 20/Apr/21

y e s . i c o r r e c t e d .

Commented by Dwaipayan Shikari last updated on 20/Apr/21

H m m s i r, b u t a n s w e r g i v e n a s \frac{7}{66}!

Commented by I want to learn more last updated on 20/Apr/21

Please sirs help me solve Q 138976