A pair of unbiased dice are rolled together till a sum of either 5 or 7 is
obtained. Then find the probability that 5 comes before 7.
Text Solution
Verified by Experts
Let A denote the event that a wim of 5 occurs, B the event that a sum of 7 occurs and C be the event that neither a sum of 5 nor a sum of 7 occurs. We have `P(A)=4/36=1/9,P(B)=6/36=1/6and P(C)=26/36=13/18` Thus, P(A occurs before B) `=1/9+((13)/(18))xx1/9+((13)/(18))^(2)1/9+...=(1//9)/(1-13//18)=2/5`
CENGAGE|Exercise ARCHIVES (MATRIX MATCH TYPE )|1 Videos
Similar Questions
Explore conceptually related problems
A die is thrown twice. Find the probability that: 5 will not come up either time
A unbiased coin is tossed. If the result is a head a pair of unbiased dice is rolled and the sum of the numbers obtained is noted. If the result is a tail, card from a well shuffled pack of eleven cards numbered 2, 3, 4, ………12 is picked and the number on the card is noted. What is the probability that the noted number is either 7 or 8?
A pair of dice is thrown until either a sum of 4 or 6 appears. Find the probability that a sum of 8 occurs first.
A pair of unbiased dice is rolled simultaneously. Find the probability of getting a difference of three.
Two unbiased dice are rolled. What is the probability of getting a sum which is neither 7 nor 11 ?
If two unbiased dice are rolled, find the probability that the total score is a prime number.
An unbiased coin is tossed. If the outcome is a head then a pair of unbiased dice is rolled and the sum of the coin results in tail, then a card from a well-shuffled pack of nine cards numbered 1,2,3,…….9 is randomly picked and the number on the card is noted. The probability that the noted number is either 7 or 8 is
