{"id":4940,"date":"2024-03-05T16:15:00","date_gmt":"2024-03-05T16:15:00","guid":{"rendered":"https:\/\/exam.pscnotes.com\/mcq\/?p=4940"},"modified":"2024-03-05T16:15:00","modified_gmt":"2024-03-05T16:15:00","slug":"if-a-man-takes-2-hrs-either-to-row-7-km-upstream-or-15-km-downstream-the-speed-of-thecurrent-in-kmph-is","status":"publish","type":"post","link":"https:\/\/exam.pscnotes.com\/mcq\/if-a-man-takes-2-hrs-either-to-row-7-km-upstream-or-15-km-downstream-the-speed-of-thecurrent-in-kmph-is\/","title":{"rendered":"If a man takes 2 hrs either to row 7 km upstream or 15 km downstream, the speed of thecurrent in (kmph) is :"},"content":{"rendered":"<p>[amp_mcq option1=&#8221;1&#8243; option2=&#8221;2&#8243; option3=&#8221;3&#8243; option4=&#8221;4&#8243; correct=&#8221;option2&#8243;]<!--more--><\/p>\n<p>The correct answer is (b) 2.<\/p>\n<p>Let $v$ be the speed of the boat in still water and $u$ be the speed of the current. The time it takes to row 7 km upstream is $7\/(v-u)$, and the time it takes to row 15 km downstream is $15\/(v+u)$. Since these times are equal, we have $7\/(v-u) = 15\/(v+u)$. Solving for $u$, we get $u = \\frac{7v+15u}{15-7v} = \\frac{7}{8}v$. The speed of the current is therefore $\\frac{7}{8}$ of the speed of the boat in still water.<\/p>\n<p>Option (a) is incorrect because it is the speed of the boat in still water, not the speed of the current. Option (c) is incorrect because it is twice the speed of the current. Option (d) is incorrect because it is four times the speed of the current.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>[amp_mcq option1=&#8221;1&#8243; option2=&#8221;2&#8243; option3=&#8221;3&#8243; option4=&#8221;4&#8243; correct=&#8221;option2&#8243;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[123],"tags":[],"class_list":["post-4940","post","type-post","status-publish","format-standard","hentry","category-kinematics","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>If a man takes 2 hrs either to row 7 km upstream or 15 km downstream, the speed of thecurrent in (kmph) is :<\/title>\n<meta name=\"description\" content=\"Let $v$ be the speed of the boat in still water and $u$ be the speed of the current. The time it takes to row 7 km upstream is $7\/(v-u)$, and the time it takes to row 15 km downstream is $15\/(v+u)$. Since these times are equal, we have $7\/(v-u) = 15\/(v+u)$. Solving for $u$, we get $u = frac{7v+15u}{15-7v} = frac{7}{8}v$. The speed of the current is therefore $frac{7}{8}$ of the speed of the boat in still water.\" \/>\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\/if-a-man-takes-2-hrs-either-to-row-7-km-upstream-or-15-km-downstream-the-speed-of-thecurrent-in-kmph-is\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"If a man takes 2 hrs either to row 7 km upstream or 15 km downstream, the speed of thecurrent in (kmph) is :\" \/>\n<meta property=\"og:description\" content=\"Let $v$ be the speed of the boat in still water and $u$ be the speed of the current. The time it takes to row 7 km upstream is $7\/(v-u)$, and the time it takes to row 15 km downstream is $15\/(v+u)$. Since these times are equal, we have $7\/(v-u) = 15\/(v+u)$. Solving for $u$, we get $u = frac{7v+15u}{15-7v} = frac{7}{8}v$. The speed of the current is therefore $frac{7}{8}$ of the speed of the boat in still water.\" \/>\n<meta property=\"og:url\" content=\"https:\/\/exam.pscnotes.com\/mcq\/if-a-man-takes-2-hrs-either-to-row-7-km-upstream-or-15-km-downstream-the-speed-of-thecurrent-in-kmph-is\/\" \/>\n<meta property=\"og:site_name\" content=\"MCQ and Quiz for Exams\" \/>\n<meta property=\"article:published_time\" content=\"2024-03-05T16:15:00+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":"If a man takes 2 hrs either to row 7 km upstream or 15 km downstream, the speed of thecurrent in (kmph) is :","description":"Let $v$ be the speed of the boat in still water and $u$ be the speed of the current. The time it takes to row 7 km upstream is $7\/(v-u)$, and the time it takes to row 15 km downstream is $15\/(v+u)$. Since these times are equal, we have $7\/(v-u) = 15\/(v+u)$. Solving for $u$, we get $u = frac{7v+15u}{15-7v} = frac{7}{8}v$. The speed of the current is therefore $frac{7}{8}$ of the speed of the boat in still water.","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\/if-a-man-takes-2-hrs-either-to-row-7-km-upstream-or-15-km-downstream-the-speed-of-thecurrent-in-kmph-is\/","og_locale":"en_US","og_type":"article","og_title":"If a man takes 2 hrs either to row 7 km upstream or 15 km downstream, the speed of thecurrent in (kmph) is :","og_description":"Let $v$ be the speed of the boat in still water and $u$ be the speed of the current. The time it takes to row 7 km upstream is $7\/(v-u)$, and the time it takes to row 15 km downstream is $15\/(v+u)$. Since these times are equal, we have $7\/(v-u) = 15\/(v+u)$. Solving for $u$, we get $u = frac{7v+15u}{15-7v} = frac{7}{8}v$. The speed of the current is therefore $frac{7}{8}$ of the speed of the boat in still water.","og_url":"https:\/\/exam.pscnotes.com\/mcq\/if-a-man-takes-2-hrs-either-to-row-7-km-upstream-or-15-km-downstream-the-speed-of-thecurrent-in-kmph-is\/","og_site_name":"MCQ and Quiz for Exams","article_published_time":"2024-03-05T16:15:00+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\/if-a-man-takes-2-hrs-either-to-row-7-km-upstream-or-15-km-downstream-the-speed-of-thecurrent-in-kmph-is\/","url":"https:\/\/exam.pscnotes.com\/mcq\/if-a-man-takes-2-hrs-either-to-row-7-km-upstream-or-15-km-downstream-the-speed-of-thecurrent-in-kmph-is\/","name":"If a man takes 2 hrs either to row 7 km upstream or 15 km downstream, the speed of thecurrent in (kmph) is :","isPartOf":{"@id":"https:\/\/exam.pscnotes.com\/mcq\/#website"},"datePublished":"2024-03-05T16:15:00+00:00","dateModified":"2024-03-05T16:15:00+00:00","author":{"@id":"https:\/\/exam.pscnotes.com\/mcq\/#\/schema\/person\/5807dafeb27d2ec82344d6cbd6c3d209"},"description":"Let $v$ be the speed of the boat in still water and $u$ be the speed of the current. The time it takes to row 7 km upstream is $7\/(v-u)$, and the time it takes to row 15 km downstream is $15\/(v+u)$. Since these times are equal, we have $7\/(v-u) = 15\/(v+u)$. Solving for $u$, we get $u = \\frac{7v+15u}{15-7v} = \\frac{7}{8}v$. The speed of the current is therefore $\\frac{7}{8}$ of the speed of the boat in still water.","breadcrumb":{"@id":"https:\/\/exam.pscnotes.com\/mcq\/if-a-man-takes-2-hrs-either-to-row-7-km-upstream-or-15-km-downstream-the-speed-of-thecurrent-in-kmph-is\/#breadcrumb"},"inLanguage":"en-US","potentialAction":[{"@type":"ReadAction","target":["https:\/\/exam.pscnotes.com\/mcq\/if-a-man-takes-2-hrs-either-to-row-7-km-upstream-or-15-km-downstream-the-speed-of-thecurrent-in-kmph-is\/"]}]},{"@type":"BreadcrumbList","@id":"https:\/\/exam.pscnotes.com\/mcq\/if-a-man-takes-2-hrs-either-to-row-7-km-upstream-or-15-km-downstream-the-speed-of-thecurrent-in-kmph-is\/#breadcrumb","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https:\/\/exam.pscnotes.com\/mcq\/"},{"@type":"ListItem","position":2,"name":"mcq","item":"https:\/\/exam.pscnotes.com\/mcq\/category\/mcq\/"},{"@type":"ListItem","position":3,"name":"kinematics","item":"https:\/\/exam.pscnotes.com\/mcq\/category\/mcq\/kinematics\/"},{"@type":"ListItem","position":4,"name":"If a man takes 2 hrs either to row 7 km upstream or 15 km downstream, the speed of thecurrent in (kmph) is :"}]},{"@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\/4940","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=4940"}],"version-history":[{"count":0,"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/posts\/4940\/revisions"}],"wp:attachment":[{"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/media?parent=4940"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/categories?post=4940"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/tags?post=4940"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}