SOLUTION: How many throws of two dice are needed, on average, to roll a lucky seven?

Question 232446: How many throws of two dice are needed, on average, to roll a lucky seven?
Answer by vincysam(2) (Show Source): You can put this solution on YOUR website!
The total number of possible outcomes when two dice are thrown are 36
Possible out comes are one on first die and one on second die (1,1)
one on first die and two on second die (1,2)
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six on first die and five on second die (6,5)
six on first die and six on second die (6,6)
Favorable chances to get seven is (1,6),(2,5),(3,4),(4,3),(5,2),(6,1)
Probability of getting seven = favorable chances to roll seven/total outcomes
= 6/36
= 1/6
This means on average six throws need to roll lucky seven

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