{"id":215299,"date":"2025-05-16T17:10:34","date_gmt":"2025-05-16T17:10:34","guid":{"rendered":"https:\/\/learnexams.com\/blog\/?p=215299"},"modified":"2025-05-16T17:10:36","modified_gmt":"2025-05-16T17:10:36","slug":"a-machine-costs-n3000-and-has-a-lifespan-of-8-years-after-which-it-can-be-sold-for-n600-7","status":"publish","type":"post","link":"https:\/\/www.learnexams.com\/blog\/2025\/05\/16\/a-machine-costs-n3000-and-has-a-lifespan-of-8-years-after-which-it-can-be-sold-for-n600-7\/","title":{"rendered":"A machine costs N3,000 and has a lifespan of 8 years, after which it can be sold for N600."},"content":{"rendered":"\n<p>A machine costs N3,000 and has a lifespan of 8 years, after which it can be sold for N600.<\/p>\n\n\n\n<p>An alternative machine costs N4,000, also with a lifespan of 8 years, but its resale value at the end of its life is N1,900.<\/p>\n\n\n\n<p>At what annual discount rate (compounded annually) would it be equally economical to choose either machine? (Ignore taxes.)<\/p>\n\n\n\n<p><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-ast-global-color-1-color\">The Correct Answer and Explanation is:<\/mark><\/strong><\/p>\n\n\n\n<p>To find the annual <strong>discount rate<\/strong> at which both machines are <strong>equally economical<\/strong>, we need to compare the <strong>present value (PV) of their costs<\/strong> over their 8-year lifespans.<\/p>\n\n\n\n<p>Let\u2019s define:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>C\u2081 = N3,000<\/strong>, <strong>S\u2081 = N600<\/strong> (resale value), lifespan = 8 years<\/li>\n\n\n\n<li><strong>C\u2082 = N4,000<\/strong>, <strong>S\u2082 = N1,900<\/strong> (resale value), lifespan = 8 years<\/li>\n\n\n\n<li>Let <strong>r<\/strong> be the annual discount rate (compounded annually)<\/li>\n<\/ul>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">Step 1: Net Present Cost Formula<\/h3>\n\n\n\n<p>The <strong>present cost<\/strong> of each machine is:<\/p>\n\n\n\n<p>$$<br>\\text{Net Present Cost} = \\text{Initial Cost} &#8211; \\frac{\\text{Salvage Value}}{(1 + r)^n}<br>$$<\/p>\n\n\n\n<p>Where:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>$r$ = annual discount rate<\/li>\n\n\n\n<li>$n$ = lifespan = 8 years<\/li>\n<\/ul>\n\n\n\n<p>Set the <strong>net present cost of both machines equal<\/strong>:<\/p>\n\n\n\n<p>$$<br>3000 &#8211; \\frac{600}{(1 + r)^8} = 4000 &#8211; \\frac{1900}{(1 + r)^8}<br>$$<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">Step 2: Solve the Equation<\/h3>\n\n\n\n<p>Move all terms to one side:<\/p>\n\n\n\n<p>$$<br>3000 &#8211; 4000 = \\frac{600 &#8211; 1900}{(1 + r)^8}<br>$$<\/p>\n\n\n\n<p>$$<br>-1000 = \\frac{-1300}{(1 + r)^8}<br>$$<\/p>\n\n\n\n<p>Multiply both sides by $(1 + r)^8$:<\/p>\n\n\n\n<p>$$<br>-1000(1 + r)^8 = -1300<br>$$<\/p>\n\n\n\n<p>Divide both sides by -1000:<\/p>\n\n\n\n<p>$$<br>(1 + r)^8 = \\frac{1300}{1000} = 1.3<br>$$<\/p>\n\n\n\n<p>Take the 8th root of both sides:<\/p>\n\n\n\n<p>$$<br>1 + r = (1.3)^{1\/8}<br>$$<\/p>\n\n\n\n<p>Using a calculator:<\/p>\n\n\n\n<p>$$<br>(1.3)^{1\/8} \\approx 1.0332<br>$$<\/p>\n\n\n\n<p>$$<br>r = 1.0332 &#8211; 1 = 0.0332 \\text{ or } 3.32\\%<br>$$<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">\u2705 <strong>Final Answer: 3.32% annual discount rate<\/strong><\/h3>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">\ud83d\udd0d <strong>Explanation (300+ words)<\/strong><\/h3>\n\n\n\n<p>To determine which machine is more economical, we use the <strong>present value<\/strong> approach, which helps compare money spent or saved at different points in time. Since both machines last 8 years and provide similar services, the main difference lies in their <strong>initial cost<\/strong> and <strong>salvage (resale) value<\/strong>.<\/p>\n\n\n\n<p>The concept of <strong>discounting<\/strong> helps us find how much future money (like resale value) is worth in today&#8217;s terms. A higher discount rate makes future money less valuable today.<\/p>\n\n\n\n<p>We calculate each machine\u2019s <strong>net present cost<\/strong>, which is the initial cost minus the present value of the resale value. This is because we &#8220;recover&#8221; some money at the end by selling the machine.<\/p>\n\n\n\n<p>For both machines to be equally economical, their <strong>net present costs<\/strong> must be the same. We set up an equation that expresses this equality and solve it to find the discount rate.<\/p>\n\n\n\n<p>The solution involves solving an equation where the only unknown is the <strong>discount rate $r$<\/strong>. Using algebra and exponentiation, we find that the value of $r$ that satisfies the condition is approximately <strong>3.32% per year<\/strong>, compounded annually.<\/p>\n\n\n\n<p>This means that if the time value of money (or cost of capital) is exactly 3.32%, both machines are financially equivalent over their lifespan. If the actual discount rate is <strong>higher than 3.32%<\/strong>, the cheaper machine (N3,000) is preferable. If the rate is <strong>lower<\/strong>, the more expensive machine with the higher salvage value (N4,000) becomes more economical in the long run.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>A machine costs N3,000 and has a lifespan of 8 years, after which it can be sold for N600. An alternative machine costs N4,000, also with a lifespan of 8 years, but its resale value at the end of its life is N1,900. At what annual discount rate (compounded annually) would it be equally economical [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[25],"tags":[],"class_list":["post-215299","post","type-post","status-publish","format-standard","hentry","category-exams-certification"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/215299","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/comments?post=215299"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/215299\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=215299"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=215299"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=215299"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}