A die is thrown again and again until three sixes are obtained. Find the probability of obtaining the third six in the sixth throw of the die.

Explanation

6 in 6th throw`= 1/6`

`n=5, p=1/6, q=5/6`

p(x=2)`= .^5C_2 (1/6)^2(5/6)^3`

`= (5*4)/(2*1)*5^3/6^5= 2*5^4/6^5`

total probability`= 2*5^4/6^5*1/6`

`=625/23328`

answer