Tom learns to cook

7780 /www/nrich/html/content/id/7780/ 1 2011-09-23T16:01:08 <?xml version="1.0" encoding="UTF-8"?> <mdoxml version="1.0"> <ul id="stemLinks"> <li><a href="http://nrich.maths.org/7030">Warm-up</a></li> <li><a href="http://nrich.maths.org/5973">Try this next</a></li> <li><a href="http://nrich.maths.org/7466">Think higher</a></li> <li><a href="http://nrich.maths.org/2589">Read: mathematics</a></li> <li><a href="http://www.scienceofcooking.com/">Read: science</a></li> <li><a href="http://en.wikipedia.org/wiki/Decision_making">Explore further</a></li> </ul> Tom has decided that the time has come - if he wants to eat, he's going to have to learn to cook. His favourite meal is poached eggs and baked beans on toast, so he asks his friend Alison to show him how to make it. Alison wants to make sure that she doesn't end up cooking it for him, so rather than showing him, she gives him <a href="/content/id/7780/TomLearnsToCook.pdf">a set of instruction cards</a>. All Tom has to do is to put them in the right order, then follow the instructions. Put the cards in the right order, and see what time Tom should get started, if he wants his supper to be ready by 7pm. <ul> <li>When should he put the water onto boil for the eggs?</li> <li>When should he put the toast on?</li> <li>When should he put the beans on?</li> </ul> </mdoxml> <?xml version="1.0" encoding="UTF-8"?> <mdoxml version="1.0">First put the cards in order. We can focus on the eggs, beans and toast separately to start with, then see how they need to be integrated into a single plan. The eggs: <ol> <li>Fill a small pan with water to a depth of about 3 inches or 8cm.</li> <li>Bring the water to the boil.</li> <li>As the water comes to the boil, add a dessert-spoon of vinegar and turn the heat down so the water is just simmering.</li> <li>Gently add the eggs to the simmering water and continue to simmer for about 3 minutes.</li> <li>Lift the eggs carefully out of the water with a slotted spoon and gently place on the toast.</li> </ol> The toast: <ol> <li>Put two slices of bread in the toaster.</li> <li>Put two slices of toast on the plate.</li> </ol> The beans: <ol> <li>Open the can of beans and put as much as you want into a small pan.</li> <li>Bring the beans to the boil and simmer gently until everything else is ready - but don't let them get too dry.</li> </ol> Tom wants everything ready for 7pm. The eggs take a total of roughly 8 to 12 minutes, depending on how quickly the water comes to the boil. The toast will take a minute or two. The beans will take a few minutes, depending on how much of the tin Tom uses. The eggs will take longest so they should be started first, with the final stage of cooking the eggs coinciding with making the toast and heating the beans. So Tom might do things in this order: <ol> <li>Fill a small pan with water to a depth of about 3 inches or 8cm.</li> <li>Bring the water to the boil.</li> <li>Open the can of beans and put as much as you want into a small pan.</li> <li>As the water comes to the boil, add a dessert-spoon of vinegar and turn the heat down so the water is just simmering.</li> <li>Gently add the eggs to the simmering water and continue to simmer for about 3 minutes.</li> <li>Bring the beans to the boil and simmer gently until everything else is ready - but don't let them get too dry.</li> <li>Put two slices of bread in the toaster.</li> <li>Put two slices of toast on the plate.</li> <li>Lift the eggs carefully out of the water with a slotted spoon and gently place on the toast.</li> </ol> Tom should get the water onto boil for the eggs about 6.50pm, putting the beans on about 6.57pm and putting on the toast about 6.58pm.</mdoxml> <?xml version="1.0" encoding="UTF-8"?> <mdoxml version="1.0"><h3>Why do this problem?</h3> This is one of a series of problems which students might encounter in Food Technology. <a href="http://nrich.maths.org/7780">The problem</a> originated in a real situation when someone cooked a beautiful meal, only noticing in the last five minutes that the recipe said 'Serve with rice' - by which time it was too late, if the rest wasn't to be ruined. Mathematically, it gives practice in organising information. The cards provided should be put in order, then a timeline can be drawn up. To put the cards in order, students will need to know, find out or estimate how long some of the operations take. <h3>Key questions</h3> Do you have all the information you need to put the cards in order? If not, how can you find it? Will you start your timeline from the beginning of cooking the meal or from the end, working backwards? <h3>Possible extension</h3> <a href="http://nrich.maths.org/7466">Hmm ... when should Tom have put the rice on</a> is a similar problem, but with more complex recipes to plan. <h3>Possible support</h3> Let students discuss in groups what information they need but don't have, and see if the group can come up with sensible answers so that they can together put the cards in the right order.</mdoxml> <?xml version="1.0" encoding="UTF-8"?> <mdoxml version="1.0">Decide what order Tom should do the stages of cooking the eggs, beans and toast separately first, then combine them.</mdoxml> 2 3 0 1 1 0 0 Tom learns to cook If Tom wants to learn to cook his favourite supper, he needs to make a schedule so that everything is ready at the same time. Decision Mathematics and Combinatorics Logic Measures and Mensuration Time Handling, Processing and Representing Data Sorting data Applications Food technology Applications STEM - design technology