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Rock smashing competition (Posted on 2023-05-08) Difficulty: 3 of 5
Two strong-man competitors, Atlas and Brutus, are smashing large rocks with great blows of a hammer. Their goal is to smash as many rocks as they can with four strikes. They each get one point for each crumbled rock.

An unstruck rock has a 20% chance of crumbling, a rock that has been struck once but didn't crumble has a 40% chance of crumbling on its second strike, a rock struck twice has a 80% chance of crumbling on its third strike, and a rock that survives 3 strikes is guaranteed to crumble on the fourth.

What is the probability that the final score is a tie?

Note: This problem is highly adapted from a regional math competition for students up to grade 9 and calculators were not allowed. The solution was requested to two decimal places.

No Solution Yet Submitted by Jer    
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Comments: ( You must be logged in to post comments.)
  Subject Author Date
No SubjectDrew Binsky2023-06-13 20:19:11
Some ThoughtsPuzzle ThoughtsK Sengupta2023-05-08 23:09:05
Solutioncomputer solutionCharlie2023-05-08 14:22:56
re: would like to understand the contest better....Jer2023-05-08 13:32:39
SolutionSolutionLarry2023-05-08 12:51:33
Hints/Tipsre: would like to understand the contest better....Larry2023-05-08 12:48:13
would like to understand the contest better....Steven Lord2023-05-08 11:59:44
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