The minimum number of throws of a pair of dice so that the probability of getting the sum of the digits on the dice equal to 7 on atleast one throw is greater than 0.95, is n. Find n.
The Attempt at a Solution
There are 6 possible ways of getting a sum of 7.
So, P(7) = 6/36 = 1/6 and P(not 7) = 5/6
For minimum number of throws, on the last throw the sum should be 7.
(5/6)n-1 (1/6) > 0.95
(5/6)n-1 > 5.7
Solving for n gives an incorrect answer.