{"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>\r\n    <!-- Check if it's an AMP page -->\r\n            <!-- Non-AMP version -->\r\n        <div class=\"mcq-container\" data-quiz-id=\"quizState_6a9755b1a4224\">\r\n                                            <div class=\"option\" data-option-key=\"option1\" data-is-correct=\"false\">\r\n                    1                <\/div>\r\n                                            <div class=\"option\" data-option-key=\"option2\" data-is-correct=\"true\">\r\n                    2                <\/div>\r\n                                            <div class=\"option\" data-option-key=\"option3\" data-is-correct=\"false\">\r\n                    3                <\/div>\r\n                                            <div class=\"option\" data-option-key=\"option4\" data-is-correct=\"false\">\r\n                    4                <\/div>\r\n                            \r\n            <!-- Feedback messages for non-AMP -->\r\n            <div class=\"feedback\" data-feedback=\"wrong\">Answer is Right!<\/div>\r\n            <div class=\"feedback\" data-feedback=\"right\">Answer is Wrong!<\/div>\r\n        <\/div>\r\n\r\n        <script>\r\n        document.addEventListener('DOMContentLoaded', function () {\r\n            var containers = document.querySelectorAll('.mcq-container');\r\n\r\n            containers.forEach(function(container) {\r\n                var options = container.querySelectorAll('.option');\r\n                var feedbackSelect = container.querySelector('[data-feedback=\"select\"]');\r\n                var feedbackWrong = container.querySelector('[data-feedback=\"wrong\"]');\r\n                var feedbackRight = container.querySelector('[data-feedback=\"right\"]');\r\n\r\n                options.forEach(function(option) {\r\n                    option.addEventListener('click', function() {\r\n                        var selectedOption = option.getAttribute('data-option-key');\r\n                        var isCorrect = option.getAttribute('data-is-correct') === 'true';\r\n\r\n                        \/\/ Remove previous selections\r\n                        options.forEach(function(opt) {\r\n                            opt.classList.remove('correct', 'incorrect');\r\n                        });\r\n\r\n                        \/\/ Add the correct\/incorrect class\r\n                        if (isCorrect) {\r\n                            option.classList.add('correct');\r\n                            feedbackRight.hidden = false;\r\n                            feedbackWrong.hidden = true;\r\n                        } else {\r\n                            option.classList.add('incorrect');\r\n                            feedbackRight.hidden = true;\r\n                            feedbackWrong.hidden = false;\r\n                        }\r\n\r\n                        \/\/ Hide select feedback\r\n                        feedbackSelect.hidden = true;\r\n                    });\r\n                });\r\n            });\r\n        });\r\n        <\/script>\r\n    \r\n    <!--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 <div class=\"telegram-channel-container\">\r\n        <a href=\"https:\/\/t.me\/pscnotes2025\" target=\"_blank\" class=\"telegram-channel-button\">\r\n            <span class=\"telegram-icon\">\r\n                <svg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" viewBox=\"0 0 496 512\">\r\n                    <path fill=\"white\" d=\"M248,8C111,8,0,119,0,256s111,248,248,248s248-111,248-248S385,8,248,8z M362,177L320,367c-3,14-10,18-20,14l-56-41l-27,26 c-3,3-5,5-10,5l4-63L323,196c5-5-1-7-8-3l-98,62l-42-13c-9-3-10-9,2-14l162-63C351,160,365,164,362,177z\"\/>\r\n                <\/svg>\r\n            <\/span>\r\n            Join Our Telegram Channel\r\n        <\/a>\r\n    <\/div> 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. <div class=\"youtube-subscribe-container\">\r\n        <a href=\"https:\/\/www.youtube.com\/channel\/UCNHT8lW-JmLC68rjBfZhdkg?sub_confirmation=1\" target=\"_blank\" class=\"youtube-subscribe-button\">\r\n            <span class=\"youtube-icon\">\r\n                <svg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" viewBox=\"0 0 576 512\">\r\n                    <path d=\"M549.7 124.1c-6.3-23.7-24.8-42.3-48.3-48.6C458.8 64 288 64 288 64S117.2 64 74.6 75.5c-23.5 6.3-42 24.9-48.3 48.6-11.4 42.9-11.4 132.3-11.4 132.3s0 89.4 11.4 132.3c6.3 23.7 24.8 41.5 48.3 47.8C117.2 448 288 448 288 448s170.8 0 213.4-11.5c23.5-6.3 42-24.2 48.3-47.8 11.4-42.9 11.4-132.3 11.4-132.3s0-89.4-11.4-132.3zm-317.5 213.5V175.2l142.7 81.2-142.7 81.2z\"\/>\r\n                <\/svg>\r\n            <\/span>\r\n            Subscribe on YouTube\r\n        <\/a>\r\n    <\/div> Option (d) is incorrect because it is four times the speed of the current.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Join Our Telegram Channel Subscribe on YouTube<\/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":[],"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\/d97f17072bfa490596c8f78363955d55?s=96&d=mm&r=g","contentUrl":"https:\/\/secure.gravatar.com\/avatar\/d97f17072bfa490596c8f78363955d55?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"}],"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}]}}