{"id":93221,"date":"2025-06-01T11:45:17","date_gmt":"2025-06-01T11:45:17","guid":{"rendered":"https:\/\/exam.pscnotes.com\/mcq\/?p=93221"},"modified":"2025-06-01T11:45:17","modified_gmt":"2025-06-01T11:45:17","slug":"two-trains-are-approaching-each-other-on-parallel-tracks-their-length","status":"publish","type":"post","link":"https:\/\/exam.pscnotes.com\/mcq\/two-trains-are-approaching-each-other-on-parallel-tracks-their-length\/","title":{"rendered":"Two trains are approaching each other on parallel tracks. Their length"},"content":{"rendered":"<p>Two trains are approaching each other on parallel tracks. Their lengths are 700 m and 400 m, respectively. The speed of the first train is 95 km\/hr and that of the second train is 125 km\/hr. The time required by the trains to cross each other is :<\/p>\n<p>[amp_mcq option1=&#8221;20 seconds&#8221; option2=&#8221;18 seconds&#8221; option3=&#8221;16 seconds&#8221; option4=&#8221;14 seconds&#8221; correct=&#8221;option2&#8243;]<\/p>\n<div class=\"psc-box-pyq-exam-year-detail\">\n<div class=\"pyq-exam\">\n<div class=\"psc-heading\">This question was previously asked in<\/div>\n<div class=\"psc-title line-ellipsis\">UPSC CISF-AC-EXE &#8211; 2023<\/div>\n<\/div>\n<div class=\"pyq-exam-psc-buttons\"><a href=\"\/pyq\/pyq-upsc-cisf-ac-exe-2023.pdf\" target=\"_blank\" class=\"psc-pdf-button\" rel=\"noopener\">Download PDF<\/a><a href=\"\/pyq-upsc-cisf-ac-exe-2023\" target=\"_blank\" class=\"psc-attempt-button\" rel=\"noopener\">Attempt Online<\/a><\/div>\n<\/div>\n<section id=\"pyq-correct-answer\">\nThe correct answer is 18 seconds. This is calculated by considering the relative speed of the trains approaching each other and the total distance they need to cover to cross each other.<br \/>\n<\/section>\n<section id=\"pyq-key-points\">\n&#8211; When two objects move towards each other, their relative speed is the sum of their individual speeds.<br \/>\n&#8211; Speed of first train = 95 km\/hr.<br \/>\n&#8211; Speed of second train = 125 km\/hr.<br \/>\n&#8211; Relative speed = 95 + 125 = 220 km\/hr.<br \/>\n&#8211; To convert km\/hr to m\/s, multiply by 5\/18: 220 km\/hr = 220 * (5\/18) m\/s = 1100\/18 m\/s = 550\/9 m\/s.<br \/>\n&#8211; The total distance the trains must cover to cross each other is the sum of their lengths.<br \/>\n&#8211; Length of first train = 700 m.<br \/>\n&#8211; Length of second train = 400 m.<br \/>\n&#8211; Total distance = 700 + 400 = 1100 m.<br \/>\n&#8211; Time taken = Total distance \/ Relative speed.<br \/>\n&#8211; Time = 1100 m \/ (550\/9 m\/s) = 1100 * (9\/550) seconds = (1100\/550) * 9 seconds = 2 * 9 seconds = 18 seconds.<br \/>\n<\/section>\n<section id=\"pyq-additional-information\">\nThis is a classic problem involving relative speed. The key is to understand that the &#8216;distance&#8217; covered when trains cross is the sum of their lengths, and when moving towards each other, their speeds add up. If they were moving in the same direction, the relative speed would be the difference between their speeds.<br \/>\n<\/section>\n","protected":false},"excerpt":{"rendered":"<p>Two trains are approaching each other on parallel tracks. Their lengths are 700 m and 400 m, respectively. The speed of the first train is 95 km\/hr and that of the second train is 125 km\/hr. The time required by the trains to cross each other is : [amp_mcq option1=&#8221;20 seconds&#8221; option2=&#8221;18 seconds&#8221; option3=&#8221;16 seconds&#8221; &#8230; <\/p>\n<p class=\"read-more-container\"><a title=\"Two trains are approaching each other on parallel tracks. Their length\" class=\"read-more button\" href=\"https:\/\/exam.pscnotes.com\/mcq\/two-trains-are-approaching-each-other-on-parallel-tracks-their-length\/#more-93221\">Detailed Solution<span class=\"screen-reader-text\">Two trains are approaching each other on parallel tracks. Their length<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1089],"tags":[1105,1102],"class_list":["post-93221","post","type-post","status-publish","format-standard","hentry","category-upsc-cisf-ac-exe","tag-1105","tag-quantitative-aptitude-and-reasoning","no-featured-image-padding"],"yoast_head":"<!-- This site is optimized with the Yoast SEO Premium plugin v22.2 (Yoast SEO v23.3) - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>Two trains are approaching each other on parallel tracks. Their length<\/title>\n<meta name=\"description\" content=\"The correct answer is 18 seconds. This is calculated by considering the relative speed of the trains approaching each other and the total distance they need to cover to cross each other. - When two objects move towards each other, their relative speed is the sum of their individual speeds. - Speed of first train = 95 km\/hr. - Speed of second train = 125 km\/hr. - Relative speed = 95 + 125 = 220 km\/hr. - To convert km\/hr to m\/s, multiply by 5\/18: 220 km\/hr = 220 * (5\/18) m\/s = 1100\/18 m\/s = 550\/9 m\/s. - The total distance the trains must cover to cross each other is the sum of their lengths. - Length of first train = 700 m. - Length of second train = 400 m. - Total distance = 700 + 400 = 1100 m. - Time taken = Total distance \/ Relative speed. - Time = 1100 m \/ (550\/9 m\/s) = 1100 * (9\/550) seconds = (1100\/550) * 9 seconds = 2 * 9 seconds = 18 seconds.\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/exam.pscnotes.com\/mcq\/two-trains-are-approaching-each-other-on-parallel-tracks-their-length\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Two trains are approaching each other on parallel tracks. Their length\" \/>\n<meta property=\"og:description\" content=\"The correct answer is 18 seconds. This is calculated by considering the relative speed of the trains approaching each other and the total distance they need to cover to cross each other. - When two objects move towards each other, their relative speed is the sum of their individual speeds. - Speed of first train = 95 km\/hr. - Speed of second train = 125 km\/hr. - Relative speed = 95 + 125 = 220 km\/hr. - To convert km\/hr to m\/s, multiply by 5\/18: 220 km\/hr = 220 * (5\/18) m\/s = 1100\/18 m\/s = 550\/9 m\/s. - The total distance the trains must cover to cross each other is the sum of their lengths. - Length of first train = 700 m. - Length of second train = 400 m. - Total distance = 700 + 400 = 1100 m. - Time taken = Total distance \/ Relative speed. - Time = 1100 m \/ (550\/9 m\/s) = 1100 * (9\/550) seconds = (1100\/550) * 9 seconds = 2 * 9 seconds = 18 seconds.\" \/>\n<meta property=\"og:url\" content=\"https:\/\/exam.pscnotes.com\/mcq\/two-trains-are-approaching-each-other-on-parallel-tracks-their-length\/\" \/>\n<meta property=\"og:site_name\" content=\"MCQ and Quiz for Exams\" \/>\n<meta property=\"article:published_time\" content=\"2025-06-01T11:45:17+00:00\" \/>\n<meta name=\"author\" content=\"rawan239\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"Written by\" \/>\n\t<meta name=\"twitter:data1\" content=\"rawan239\" \/>\n\t<meta name=\"twitter:label2\" content=\"Est. reading time\" \/>\n\t<meta name=\"twitter:data2\" content=\"1 minute\" \/>\n<!-- \/ Yoast SEO Premium plugin. -->","yoast_head_json":{"title":"Two trains are approaching each other on parallel tracks. Their length","description":"The correct answer is 18 seconds. This is calculated by considering the relative speed of the trains approaching each other and the total distance they need to cover to cross each other. - When two objects move towards each other, their relative speed is the sum of their individual speeds. - Speed of first train = 95 km\/hr. - Speed of second train = 125 km\/hr. - Relative speed = 95 + 125 = 220 km\/hr. - To convert km\/hr to m\/s, multiply by 5\/18: 220 km\/hr = 220 * (5\/18) m\/s = 1100\/18 m\/s = 550\/9 m\/s. - The total distance the trains must cover to cross each other is the sum of their lengths. - Length of first train = 700 m. - Length of second train = 400 m. - Total distance = 700 + 400 = 1100 m. - Time taken = Total distance \/ Relative speed. - Time = 1100 m \/ (550\/9 m\/s) = 1100 * (9\/550) seconds = (1100\/550) * 9 seconds = 2 * 9 seconds = 18 seconds.","robots":{"index":"index","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"canonical":"https:\/\/exam.pscnotes.com\/mcq\/two-trains-are-approaching-each-other-on-parallel-tracks-their-length\/","og_locale":"en_US","og_type":"article","og_title":"Two trains are approaching each other on parallel tracks. Their length","og_description":"The correct answer is 18 seconds. This is calculated by considering the relative speed of the trains approaching each other and the total distance they need to cover to cross each other. - When two objects move towards each other, their relative speed is the sum of their individual speeds. - Speed of first train = 95 km\/hr. - Speed of second train = 125 km\/hr. - Relative speed = 95 + 125 = 220 km\/hr. - To convert km\/hr to m\/s, multiply by 5\/18: 220 km\/hr = 220 * (5\/18) m\/s = 1100\/18 m\/s = 550\/9 m\/s. - The total distance the trains must cover to cross each other is the sum of their lengths. - Length of first train = 700 m. - Length of second train = 400 m. - Total distance = 700 + 400 = 1100 m. - Time taken = Total distance \/ Relative speed. - Time = 1100 m \/ (550\/9 m\/s) = 1100 * (9\/550) seconds = (1100\/550) * 9 seconds = 2 * 9 seconds = 18 seconds.","og_url":"https:\/\/exam.pscnotes.com\/mcq\/two-trains-are-approaching-each-other-on-parallel-tracks-their-length\/","og_site_name":"MCQ and Quiz for Exams","article_published_time":"2025-06-01T11:45:17+00:00","author":"rawan239","twitter_card":"summary_large_image","twitter_misc":{"Written by":"rawan239","Est. reading time":"1 minute"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"WebPage","@id":"https:\/\/exam.pscnotes.com\/mcq\/two-trains-are-approaching-each-other-on-parallel-tracks-their-length\/","url":"https:\/\/exam.pscnotes.com\/mcq\/two-trains-are-approaching-each-other-on-parallel-tracks-their-length\/","name":"Two trains are approaching each other on parallel tracks. Their length","isPartOf":{"@id":"https:\/\/exam.pscnotes.com\/mcq\/#website"},"datePublished":"2025-06-01T11:45:17+00:00","dateModified":"2025-06-01T11:45:17+00:00","author":{"@id":"https:\/\/exam.pscnotes.com\/mcq\/#\/schema\/person\/5807dafeb27d2ec82344d6cbd6c3d209"},"description":"The correct answer is 18 seconds. This is calculated by considering the relative speed of the trains approaching each other and the total distance they need to cover to cross each other. - When two objects move towards each other, their relative speed is the sum of their individual speeds. - Speed of first train = 95 km\/hr. - Speed of second train = 125 km\/hr. - Relative speed = 95 + 125 = 220 km\/hr. - To convert km\/hr to m\/s, multiply by 5\/18: 220 km\/hr = 220 * (5\/18) m\/s = 1100\/18 m\/s = 550\/9 m\/s. - The total distance the trains must cover to cross each other is the sum of their lengths. - Length of first train = 700 m. - Length of second train = 400 m. - Total distance = 700 + 400 = 1100 m. - Time taken = Total distance \/ Relative speed. - Time = 1100 m \/ (550\/9 m\/s) = 1100 * (9\/550) seconds = (1100\/550) * 9 seconds = 2 * 9 seconds = 18 seconds.","breadcrumb":{"@id":"https:\/\/exam.pscnotes.com\/mcq\/two-trains-are-approaching-each-other-on-parallel-tracks-their-length\/#breadcrumb"},"inLanguage":"en-US","potentialAction":[{"@type":"ReadAction","target":["https:\/\/exam.pscnotes.com\/mcq\/two-trains-are-approaching-each-other-on-parallel-tracks-their-length\/"]}]},{"@type":"BreadcrumbList","@id":"https:\/\/exam.pscnotes.com\/mcq\/two-trains-are-approaching-each-other-on-parallel-tracks-their-length\/#breadcrumb","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https:\/\/exam.pscnotes.com\/mcq\/"},{"@type":"ListItem","position":2,"name":"UPSC CISF-AC-EXE","item":"https:\/\/exam.pscnotes.com\/mcq\/category\/upsc-cisf-ac-exe\/"},{"@type":"ListItem","position":3,"name":"Two trains are approaching each other on parallel tracks. Their length"}]},{"@type":"WebSite","@id":"https:\/\/exam.pscnotes.com\/mcq\/#website","url":"https:\/\/exam.pscnotes.com\/mcq\/","name":"MCQ and Quiz for Exams","description":"","potentialAction":[{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https:\/\/exam.pscnotes.com\/mcq\/?s={search_term_string}"},"query-input":"required name=search_term_string"}],"inLanguage":"en-US"},{"@type":"Person","@id":"https:\/\/exam.pscnotes.com\/mcq\/#\/schema\/person\/5807dafeb27d2ec82344d6cbd6c3d209","name":"rawan239","image":{"@type":"ImageObject","inLanguage":"en-US","@id":"https:\/\/exam.pscnotes.com\/mcq\/#\/schema\/person\/image\/","url":"https:\/\/secure.gravatar.com\/avatar\/761a7274f9cce048fa5b921221e7934820d74514df93ef195a9d22af0c1c9001?s=96&d=mm&r=g","contentUrl":"https:\/\/secure.gravatar.com\/avatar\/761a7274f9cce048fa5b921221e7934820d74514df93ef195a9d22af0c1c9001?s=96&d=mm&r=g","caption":"rawan239"},"sameAs":["https:\/\/exam.pscnotes.com"],"url":"https:\/\/exam.pscnotes.com\/mcq\/author\/rawan239\/"}]}},"amp_enabled":true,"_links":{"self":[{"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/posts\/93221","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/comments?post=93221"}],"version-history":[{"count":0,"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/posts\/93221\/revisions"}],"wp:attachment":[{"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/media?parent=93221"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/categories?post=93221"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/tags?post=93221"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}