Can you solve this tricky 2017 PSLE Math question on ribbons?

Can you solve this tricky 2017 PSLE Math question on ribbons?

Think first.

Copy and paste this URL into your WordPress site to embed

<blockquote class="wp-embedded-content"><a href="https://mothership.sg/2017/10/can-you-solve-this-tricky-2017-psle-math-question-on-ribbons/">Think first. </a></blockquote> <script type='text/javascript'> <!--//--><![CDATA[//><!-- !function(d,l){"use strict";var e=!1,o=!1;if(l.querySelector)if(d.addEventListener)e=!0;if(d.wp=d.wp||{},!d.wp.receiveEmbedMessage)if(d.wp.receiveEmbedMessage=function(e){var t=e.data;if(t)if(t.secret||t.message||t.value)if(!/[^a-zA-Z0-9]/.test(t.secret)){var r,a,i,s,n,o=l.querySelectorAll('iframe[data-secret="'+t.secret+'"]'),c=l.querySelectorAll('blockquote[data-secret="'+t.secret+'"]');for(r=0;r<c.length;r++)c[r].style.display="none";for(r=0;r<o.length;r++)if(a=o[r],e.source===a.contentWindow){if(a.removeAttribute("style"),"height"===t.message){if(1e3<(i=parseInt(t.value,10)))i=1e3;else if(~~i<200)i=200;a.height=i}if("link"===t.message)if(s=l.createElement("a"),n=l.createElement("a"),s.href=a.getAttribute("src"),n.href=t.value,n.host===s.host)if(l.activeElement===a)d.top.location.href=t.value}}},e)d.addEventListener("message",d.wp.receiveEmbedMessage,!1),l.addEventListener("DOMContentLoaded",t,!1),d.addEventListener("load",t,!1);function t(){if(!o){o=!0;var e,t,r,a,i=-1!==navigator.appVersion.indexOf("MSIE 10"),s=!!navigator.userAgent.match(/Trident.*rv:11\./),n=l.querySelectorAll("iframe.wp-embedded-content");for(t=0;t<n.length;t++){if(!(r=n[t]).getAttribute("data-secret"))a=Math.random().toString(36).substr(2,10),r.src+="#?secret="+a,r.setAttribute("data-secret",a);if(i||s)(e=r.cloneNode(!0)).removeAttribute("security"),r.parentNode.replaceChild(e,r)}}}}(window,document); //--><!]]> </script><iframe sandbox="allow-scripts" security="restricted" src="https://mothership.sg/2020/04/pm-lee-singaporeans-dont-go-out/embed/" width="600" height="400" title="&#8220;PM Lee: S&#8217;poreans should go out only if &#8216;essential&#8217;, stay at home as much as possible&#8221; &#8212; Mothership.SG - News from Singapore, Asia and around the world" frameborder="0" marginwidth="0" marginheight="0" scrolling="no" class="wp-embedded-content"></iframe>

Copy and paste this code into your site to embed