[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"doc-seo-631373-105":3,"detail-sidebar-cat-0-en-105":80,"doc-detail-631373-en":130},{"code":4,"msg":5,"data":6},0,"ok",{"site_id":7,"language":8,"slug":9,"title":10,"keywords":11,"description":12,"schema_data":13,"social_meta":73,"head_meta":75,"extra_data":77,"updated_unix":79},105,"en","dont-be-alarmed-light-timing-puzzle-answer-and-solution","DON’T BE ALARMED - Light Timing Puzzle - Answer and Solution","","A burglar alarm system switches three house lights on and off while the family is away. Light 1 is on for 3 minutes then off for 3 minutes, Light 2 cycles on for 5 minutes then off for 5 minutes, and Light 3 cycles on for 2 minutes then off for 2 minutes. The lights start together and the question asks when they will all be off at the same time, followed by when they will all be on again together.",{"@graph":14,"@context":72},[15,34,55],{"@type":16,"itemListElement":17},"BreadcrumbList",[18,23,27,31],{"item":19,"name":20,"@type":21,"position":22},"https://docshare.wps.com","Home","ListItem",1,{"item":24,"name":25,"@type":21,"position":26},"https://docshare.wps.com/document/","Document",2,{"item":28,"name":29,"@type":21,"position":30},"https://docshare.wps.com/document/exam/","Exam",3,{"item":32,"name":10,"@type":21,"position":33},"https://docshare.wps.com/document/dont-be-alarmed-light-timing-puzzle-answer-and-solution/631373/",4,{"url":32,"name":10,"@type":35,"image":36,"author":41,"headline":10,"publisher":44,"fileFormat":47,"inLanguage":8,"description":12,"dateModified":48,"datePublished":49,"encodingFormat":47,"isAccessibleForFree":50,"interactionStatistic":51},"DigitalDocument",{"url":37,"@type":38,"width":39,"height":40},"https://docshare.wps.com/thumbnails/dont-be-alarmed-light-timing-puzzle-answer-and-solution/631373.png","ImageObject",300,407,{"name":42,"@type":43},"Lucas Martin","Person",{"url":19,"name":45,"@type":46},"DocShare","Organization","application/pdf","2026-11-04","2026-10-22",true,{"@type":52,"interactionType":53,"userInteractionCount":30},"InteractionCounter",{"@type":54},"ViewAction",{"@type":56,"mainEntity":57},"FAQPage",[58,64,68],{"name":59,"@type":60,"acceptedAnswer":61},"How does each light cycle in the burglar alarm system?","Question",{"text":62,"@type":63},"Light 1 turns on for 3 minutes then off for 3 minutes; Light 2 turns on for 5 minutes then off for 5 minutes; Light 3 turns on for 2 minutes then off for 2 minutes.","Answer",{"name":65,"@type":60,"acceptedAnswer":66},"After how long are all three lights off at the same time?",{"text":67,"@type":63},"They are all off after 15 minutes, in the 16th minute.",{"name":69,"@type":60,"acceptedAnswer":70},"When do all three lights come on again together?",{"text":71,"@type":63},"After 60 minutes.","https://schema.org",{"og:url":32,"og:type":74,"og:title":10,"og:site_name":45,"og:description":12},"article",{"robots":76,"canonical":32},"index,follow",{"doc_id":78,"site_id":7},631373,1792669014,{"code":4,"msg":81,"data":82},"success",[83,87,91,94,99,104,109,114,119,122,126],{"id":22,"doc_module":4,"doc_module_name":25,"category_name":84,"show_sort_weight":85,"slug":86},"Story & Novel",90,"story-novel",{"id":26,"doc_module":4,"doc_module_name":25,"category_name":88,"show_sort_weight":89,"slug":90},"Literature",80,"literature",{"id":33,"doc_module":4,"doc_module_name":25,"category_name":29,"show_sort_weight":92,"slug":93},70,"exam",{"id":95,"doc_module":4,"doc_module_name":25,"category_name":96,"show_sort_weight":97,"slug":98},5,"Comic",60,"comic",{"id":100,"doc_module":4,"doc_module_name":25,"category_name":101,"show_sort_weight":102,"slug":103},6,"Technology",50,"technology",{"id":105,"doc_module":4,"doc_module_name":25,"category_name":106,"show_sort_weight":107,"slug":108},7,"Healthcare",40,"healthcare",{"id":110,"doc_module":4,"doc_module_name":25,"category_name":111,"show_sort_weight":112,"slug":113},8,"Research & Report",30,"research-report",{"id":115,"doc_module":4,"doc_module_name":25,"category_name":116,"show_sort_weight":117,"slug":118},9,"Religion & Spirituality",20,"religion-spirituality",{"id":117,"doc_module":4,"doc_module_name":25,"category_name":120,"show_sort_weight":117,"slug":121},"World Cup","world-cup",{"id":123,"doc_module":4,"doc_module_name":25,"category_name":124,"show_sort_weight":123,"slug":125},10,"Lifestyle","lifestyle",{"id":127,"doc_module":4,"doc_module_name":25,"category_name":128,"show_sort_weight":95,"slug":129},19,"General","general",{"code":4,"msg":81,"data":131},{"doc_id":78,"user_id":132,"nickname":42,"user_avatar":133,"doc_module":4,"category_id":33,"category_name":29,"doc_title":10,"doc_description":12,"doc_content":134,"file_id":135,"file_url":136,"file_type":137,"file_size":138,"view_count":30,"is_deleted":4,"is_public":22,"is_downloadable":22,"audit_status":22,"page_count":26,"language":139,"language_code":8,"site_id":7,"html_lang":8,"table_of_contents":140,"faqs":141,"seo_title":142,"seo_description":12,"update_tm":79,"read_time":95},8796095360427,"https://ap-avatar.wpscdn.com/davatar_994ba38a5ba835b3df7d355c54d3ed8d","DON’T BE ALARMED  \nA burglar alarm system turns three of the lights in the house on and off while the family are away.  \nThe alarm turns the first light on for three minutes, then off for three minutes. The alarm turns the second light on for five minutes and then off for five minutes. The alarm turns the third light on for two minutes, then off for two minutes. The lights have all just gone on. How long will it be until all the lights are off at the same time?  \nHow long will it be until all the lights come on again, all at the same time?  \nDON’T BE ALARMED ANSWERS  \nA burglar alarm system turns three of the lights in the house on and off while the family are away.  \nThe alarm turns the first light on for three minutes, then off for three minutes. The alarm turns the second light on for five minutes and then off for five minutes. The alarm turns the third light on for two minutes, then off for two minutes. The lights have all just gone on. How long will it be until all the lights are off at the same time?  \nAnswer: they are all off after 15 minutes (in the 16th minute) .  \n\n|  | Minutes |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |\n| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |\n|  | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 |\n| Light 1 | ✓ | ✓ | ✓ | X | X | X | ✓ | ✓ | ✓ | X | X | X | ✓ | ✓ | ✓ | X | X | X | ✓ | ✓ |\n| Light 2 | ✓ | ✓ | ✓ | ✓ | ✓ | X | X | X | X | X | ✓ | ✓ | ✓ | ✓ | ✓ | X | X | X | X | X |\n| Light 3 | ✓ | ✓ | X | X | ✓ | ✓ | X | X | ✓ | ✓ | X | X | ✓ | ✓ | X | X | ✓ | ✓ | X | X |\n\nHow long will it be until all the lights come on again, all at the same time?  \nAfter 60 minutes  \n\n|  | Time lights come on after…(minutes) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |\n| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |\n| Light 1 | 0 | 6 | 12 | 18 | 24 | 30 | 36 | 42 | 48 | 54 | 60 | 66 | 72 | 78 | 84 | 90 | 96 | 102 |\n| Light 2 | 0 | 10 | 20 | 30 | 40 | 50 | 60 | 70 | 80 | 90 | 100 | 110 | 120 | 130 | 140 | 150 |  |  |\n| Light 3 | 0 | 4 | 8 | 12 | 16 | 20 | 24 | 28 | 32 | 36 | 40 | 44 | 48 | 52 | 56 | 60 | 64 | 68 |","cbCaiu3fMRHQF2I1","https://ap.wps.com/l/cbCaiu3fMRHQF2I1","pdf",191590,"English","# Problem\n## All lights off together\n## All lights on together","[{\"question\":\"How does each light cycle in the burglar alarm system?\",\"answer\":\"Light 1 turns on for 3 minutes then off for 3 minutes; Light 2 turns on for 5 minutes then off for 5 minutes; Light 3 turns on for 2 minutes then off for 2 minutes.\"},{\"question\":\"After how long are all three lights off at the same time?\",\"answer\":\"They are all off after 15 minutes, in the 16th minute.\"},{\"question\":\"When do all three lights come on again together?\",\"answer\":\"After 60 minutes.\"}]","DON’T BE ALARMED - Light Timing Puzzle - Answer and Solution | PDF"]