{"group":{"id":1,"name":"Community","lockable":false,"created_at":"2012-01-18T18:02:15.000Z","updated_at":"2026-05-26T00:16:20.000Z","description":"Problems submitted by members of the MATLAB Central community.","is_default":true,"created_by":161519,"badge_id":null,"featured":false,"trending":false,"solution_count_in_trending_period":0,"trending_last_calculated":"2026-05-26T00:00:00.000Z","image_id":null,"published":true,"community_created":false,"status_id":2,"is_default_group_for_player":false,"deleted_by":null,"deleted_at":null,"restored_by":null,"restored_at":null,"description_opc":null,"description_html":null,"published_at":null},"problems":[{"id":44315,"title":"Predicting life and death of a memory-less light bulb","description":"*\u0026#128161 \u0026#128161 \u0026#128161 \u0026#128161 \u0026#128161 \u0026#128161 \u0026#128161 \u0026#128161 \u0026#128161 \u0026#128161 \u0026#128161 \u0026#128161 \u0026#128161 \u0026#128161 \u0026#128161 \u0026#128161 \u0026#128161* \r\n\r\nYou have a light bulb that can fail any moment according to the exponential probability distribution. \r\n\r\nAt any moment, the probability that it will survive just N hours = exp(-N*P), where P is a constant. \r\n\r\nNotice that this probability is very small if N is very large. \r\n\r\nNow suppose, the bulb has already survived N hours. \r\n\r\nPlease calculate the probability of its surviving M more hours.\r\n","description_html":"\u003cp\u003e\u003cb\u003e\u0026#128161 \u0026#128161 \u0026#128161 \u0026#128161 \u0026#128161 \u0026#128161 \u0026#128161 \u0026#128161 \u0026#128161 \u0026#128161 \u0026#128161 \u0026#128161 \u0026#128161 \u0026#128161 \u0026#128161 \u0026#128161 \u0026#128161\u003c/b\u003e\u003c/p\u003e\u003cp\u003eYou have a light bulb that can fail any moment according to the exponential probability distribution.\u003c/p\u003e\u003cp\u003eAt any moment, the probability that it will survive just N hours = exp(-N*P), where P is a constant.\u003c/p\u003e\u003cp\u003eNotice that this probability is very small if N is very large.\u003c/p\u003e\u003cp\u003eNow suppose, the bulb has already survived N hours.\u003c/p\u003e\u003cp\u003ePlease calculate the probability of its surviving M more hours.\u003c/p\u003e","function_template":"function hope = fate(N,P,M)\r\n  hope=exp(-(N+M)*P);\r\nend","test_suite":"%%\r\nN = 1;\r\nP=1;\r\nM=0;\r\nhope_correct = 1;\r\nassert(fate(N,P,M)\u003ehope_correct*0.999)\r\n%%\r\nN = 1;\r\nP=0;\r\nM=1;\r\nhope_correct = 1;\r\nassert(fate(N,P,M)\u003ehope_correct*0.999)\r\n%%\r\nN=1;\r\nP=1;\r\nM=1;\r\nhope_correct = 0.3679;\r\nassert(fate(N,P,M)\u003ehope_correct*0.999)\r\n%%\r\nN=2;\r\nP=1;\r\nM=1;\r\nhope_correct = 0.3679;\r\nassert(fate(N,P,M)\u003ehope_correct*0.999)\r\n%%\r\nN=2;\r\nP=1;\r\nM=2;\r\nhope_correct = 0.1353;\r\nassert(fate(N,P,M)\u003chope_correct*1.1)\r\n%%\r\nN=2;\r\nP=2;\r\nM=2;\r\nhope_correct = 0.0183;\r\nassert(fate(N,P,M)\u003chope_correct*1.1)\r\n%%","published":true,"deleted":false,"likes_count":3,"comments_count":0,"created_by":166,"edited_by":null,"edited_at":null,"deleted_by":null,"deleted_at":null,"solvers_count":377,"test_suite_updated_at":null,"rescore_all_solutions":false,"group_id":34,"created_at":"2017-09-12T02:53:45.000Z","updated_at":"2026-05-26T17:56:27.000Z","published_at":"2017-10-16T01:45:07.000Z","restored_at":null,"restored_by":null,"spam":false,"simulink":false,"admin_reviewed":false,"description_opc":"{\"relationships\":[{\"relationshipType\":\"http://schemas.mathworks.com/matlab/code/2013/relationships/document\",\"targetMode\":\"\",\"relationshipId\":\"rId1\",\"target\":\"/matlab/document.xml\"},{\"relationshipType\":\"http://schemas.mathworks.com/matlab/code/2013/relationships/output\",\"targetMode\":\"\",\"relationshipId\":\"rId2\",\"target\":\"/matlab/output.xml\"}],\"parts\":[{\"partUri\":\"/matlab/document.xml\",\"relationship\":[],\"contentType\":\"application/vnd.mathworks.matlab.code.document+xml\",\"content\":\"\u003c?xml version=\\\"1.0\\\" encoding=\\\"UTF-8\\\"?\u003e\\n\u003cw:document xmlns:w=\\\"http://schemas.openxmlformats.org/wordprocessingml/2006/main\\\"\u003e\u003cw:body\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:rPr\u003e\u003cw:b/\u003e\u003c/w:rPr\u003e\u003cw:t\u003e\u0026amp;#128161 \u0026amp;#128161 \u0026amp;#128161 \u0026amp;#128161 \u0026amp;#128161 \u0026amp;#128161 \u0026amp;#128161 \u0026amp;#128161 \u0026amp;#128161 \u0026amp;#128161 \u0026amp;#128161 \u0026amp;#128161 \u0026amp;#128161 \u0026amp;#128161 \u0026amp;#128161 \u0026amp;#128161 \u0026amp;#128161\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eYou have a light bulb that can fail any moment according to the exponential probability distribution.\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eAt any moment, the probability that it will survive just N hours = exp(-N*P), where P is a constant.\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eNotice that this probability is very small if N is very large.\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eNow suppose, the bulb has already survived N hours.\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003ePlease calculate the probability of its surviving M more hours.\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003c/w:body\u003e\u003c/w:document\u003e\"},{\"partUri\":\"/matlab/output.xml\",\"contentType\":\"text/xml\",\"content\":\"\u003c?xml version=\\\"1.0\\\" encoding=\\\"UTF-8\\\" standalone=\\\"no\\\" ?\u003e\u003cembeddedOutputs\u003e\u003cmetaData\u003e\u003cevaluationState\u003emanual\u003c/evaluationState\u003e\u003clayoutState\u003ecode\u003c/layoutState\u003e\u003coutputStatus\u003eready\u003c/outputStatus\u003e\u003c/metaData\u003e\u003coutputArray type=\\\"array\\\"/\u003e\u003cregionArray type=\\\"array\\\"/\u003e\u003c/embeddedOutputs\u003e\"}]}"}],"problem_search":{"problems":[{"id":44315,"title":"Predicting life and death of a memory-less light bulb","description":"*\u0026#128161 \u0026#128161 \u0026#128161 \u0026#128161 \u0026#128161 \u0026#128161 \u0026#128161 \u0026#128161 \u0026#128161 \u0026#128161 \u0026#128161 \u0026#128161 \u0026#128161 \u0026#128161 \u0026#128161 \u0026#128161 \u0026#128161* \r\n\r\nYou have a light bulb that can fail any moment according to the exponential probability distribution. \r\n\r\nAt any moment, the probability that it will survive just N hours = exp(-N*P), where P is a constant. \r\n\r\nNotice that this probability is very small if N is very large. \r\n\r\nNow suppose, the bulb has already survived N hours. \r\n\r\nPlease calculate the probability of its surviving M more hours.\r\n","description_html":"\u003cp\u003e\u003cb\u003e\u0026#128161 \u0026#128161 \u0026#128161 \u0026#128161 \u0026#128161 \u0026#128161 \u0026#128161 \u0026#128161 \u0026#128161 \u0026#128161 \u0026#128161 \u0026#128161 \u0026#128161 \u0026#128161 \u0026#128161 \u0026#128161 \u0026#128161\u003c/b\u003e\u003c/p\u003e\u003cp\u003eYou have a light bulb that can fail any moment according to the exponential probability distribution.\u003c/p\u003e\u003cp\u003eAt any moment, the probability that it will survive just N hours = exp(-N*P), where P is a constant.\u003c/p\u003e\u003cp\u003eNotice that this probability is very small if N is very large.\u003c/p\u003e\u003cp\u003eNow suppose, the bulb has already survived N hours.\u003c/p\u003e\u003cp\u003ePlease calculate the probability of its surviving M more hours.\u003c/p\u003e","function_template":"function hope = fate(N,P,M)\r\n  hope=exp(-(N+M)*P);\r\nend","test_suite":"%%\r\nN = 1;\r\nP=1;\r\nM=0;\r\nhope_correct = 1;\r\nassert(fate(N,P,M)\u003ehope_correct*0.999)\r\n%%\r\nN = 1;\r\nP=0;\r\nM=1;\r\nhope_correct = 1;\r\nassert(fate(N,P,M)\u003ehope_correct*0.999)\r\n%%\r\nN=1;\r\nP=1;\r\nM=1;\r\nhope_correct = 0.3679;\r\nassert(fate(N,P,M)\u003ehope_correct*0.999)\r\n%%\r\nN=2;\r\nP=1;\r\nM=1;\r\nhope_correct = 0.3679;\r\nassert(fate(N,P,M)\u003ehope_correct*0.999)\r\n%%\r\nN=2;\r\nP=1;\r\nM=2;\r\nhope_correct = 0.1353;\r\nassert(fate(N,P,M)\u003chope_correct*1.1)\r\n%%\r\nN=2;\r\nP=2;\r\nM=2;\r\nhope_correct = 0.0183;\r\nassert(fate(N,P,M)\u003chope_correct*1.1)\r\n%%","published":true,"deleted":false,"likes_count":3,"comments_count":0,"created_by":166,"edited_by":null,"edited_at":null,"deleted_by":null,"deleted_at":null,"solvers_count":377,"test_suite_updated_at":null,"rescore_all_solutions":false,"group_id":34,"created_at":"2017-09-12T02:53:45.000Z","updated_at":"2026-05-26T17:56:27.000Z","published_at":"2017-10-16T01:45:07.000Z","restored_at":null,"restored_by":null,"spam":false,"simulink":false,"admin_reviewed":false,"description_opc":"{\"relationships\":[{\"relationshipType\":\"http://schemas.mathworks.com/matlab/code/2013/relationships/document\",\"targetMode\":\"\",\"relationshipId\":\"rId1\",\"target\":\"/matlab/document.xml\"},{\"relationshipType\":\"http://schemas.mathworks.com/matlab/code/2013/relationships/output\",\"targetMode\":\"\",\"relationshipId\":\"rId2\",\"target\":\"/matlab/output.xml\"}],\"parts\":[{\"partUri\":\"/matlab/document.xml\",\"relationship\":[],\"contentType\":\"application/vnd.mathworks.matlab.code.document+xml\",\"content\":\"\u003c?xml version=\\\"1.0\\\" encoding=\\\"UTF-8\\\"?\u003e\\n\u003cw:document xmlns:w=\\\"http://schemas.openxmlformats.org/wordprocessingml/2006/main\\\"\u003e\u003cw:body\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:rPr\u003e\u003cw:b/\u003e\u003c/w:rPr\u003e\u003cw:t\u003e\u0026amp;#128161 \u0026amp;#128161 \u0026amp;#128161 \u0026amp;#128161 \u0026amp;#128161 \u0026amp;#128161 \u0026amp;#128161 \u0026amp;#128161 \u0026amp;#128161 \u0026amp;#128161 \u0026amp;#128161 \u0026amp;#128161 \u0026amp;#128161 \u0026amp;#128161 \u0026amp;#128161 \u0026amp;#128161 \u0026amp;#128161\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eYou have a light bulb that can fail any moment according to the exponential probability distribution.\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eAt any moment, the probability that it will survive just N hours = exp(-N*P), where P is a constant.\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eNotice that this probability is very small if N is very large.\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eNow suppose, the bulb has already survived N hours.\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003ePlease calculate the probability of its surviving M more hours.\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003c/w:body\u003e\u003c/w:document\u003e\"},{\"partUri\":\"/matlab/output.xml\",\"contentType\":\"text/xml\",\"content\":\"\u003c?xml version=\\\"1.0\\\" encoding=\\\"UTF-8\\\" standalone=\\\"no\\\" ?\u003e\u003cembeddedOutputs\u003e\u003cmetaData\u003e\u003cevaluationState\u003emanual\u003c/evaluationState\u003e\u003clayoutState\u003ecode\u003c/layoutState\u003e\u003coutputStatus\u003eready\u003c/outputStatus\u003e\u003c/metaData\u003e\u003coutputArray type=\\\"array\\\"/\u003e\u003cregionArray type=\\\"array\\\"/\u003e\u003c/embeddedOutputs\u003e\"}]}"}],"errors":[],"facets":[[{"value":"Cody5:Easy","count":1,"selected":false}],[{"value":"medium","count":1,"selected":false}]],"term":"tag:\"memory-less\"","page":1,"per_page":50,"sort":"map(difficulty_value,0,0,999) asc"}}