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Mrs Hurt’s real-life maths problem! Help required!

So Georgina (my daughter) bought this lasagne for tonight’s tea! (it is her turn to cook!) She needs to feed five people and needs some help to work out how to serve it … can you help? The weight is 1.5kg and the dimensions are 28L 22W 8H.

Bronze: What fraction of the lasagne should each person get? What weight of lasagne should each person get?

Silver: What surface area of the lasagne should each person get? Explain your workings. How many different ways (dimensions) could the lasagne be cut to give equal portions?

Gold: What volume of lasagne would there be in each portion? Looking at the questions in Bronze and Silver, what would the % change in weight and surface area of each portion be if we shared between 6 people instead of 5?

67 thoughts on “Mrs Hurt’s real-life maths problem! Help required!

  1. Gold: Volume would be 4928. I know this because first i did 28×22 on a paper. Then i got 616. I multiplied 616 by 8 to find the volume. Volume is WidthxHeightxLength in any order.

  2. bronze:
    each person would get 1\5 of lasagna and 300 grams.Percentage %16.5
    silver:
    22.2 cm 2
    gold:
    the volume is 985.6 cubed.
    Medina Khatun

  3. Bronze:
    Each person should get 1/5 of the beef lasagne because in the question they said there were 5 people. There was one lasagne so the numerator would be one and because there are five people so the fraction each person gets of the beef lasagne is 1/5. The waist of the beef lasagne is 1.5kg so then you do 1.5 divided by 5. So the question is 1.5 divided by 5 spans the equals 0.3. So then it is in kg because you divided it so then the weigh5 of beef lasagne each person gets is 0.3kg of beef lasagne.

    • Great job mister! However, have a look at your sentence structure! Things like punctuation and grammar are just as important when writing in maths as they are in literacy. Could you re-write this explanation for me please. Remember to start with and ‘I know that…’ sentence!

      • Bronze:
        I know that each person should get 1/5 of the lasagne. I know that because they are splitting 1 lasagne with 5 people. So that means the fraction each person gets is 1/5 because there is 1 lasagne and 5 people. I know that the weight of the lasagne is 1.5kg and they need to divide it by 5 because everybody needs to get the same amount of weight of the lasagne. So then 1.5kg divided by 5=0.3kg. So then I know that each person should get 0.3kg or 300 grams of the lasagne.

  4. Bronze:
    Each Person would get 1/5 if the lasagne. They would each get 300g of it.
    I worked this out by indicating that there are 5 people to serve. So this means that you need to divide 1.5kg by 5 (the denominator). Before doing this I converted 1.5kg into grams and that gives us 1500g. Therefore,
    1500g / 5= 300g and that is why each person gets 300g.

    Silver:
    The surface area each person should get from the lasagne is 123.2 squared (I don’t know the unit of measure as it is not mentioned). I worked this out by multiplying the length by the width (28 by 22) and this gave me 616 squared. However this is the surface area of the whole lasagne not each portion per person. In order to find how much each person should get, you need to dived it by 5 because that is how many people there are. So the calculation is: 616 / 5= 123.2 and this is how I know that the surface area for each person’s portion is 123.2.
    To give equal portions, the lasagne could be cut in equal strips from the top and could be cut by the length or width. You could also cut it in zigzags and each pice would be a triangle. But you have to ensure that the piece always weighs 300g.

    Gold:
    The volume in each portion of lasagne would be 985.6. I worked this out by knowing that the length times width is 616 (as this is what we worked out in silver) so then you need to times 616 by the height (8) to find out the volume of the whole lasagne. 616 x 8= 4928 so then you need to divide this by 5 as this is the amount of people. This gives you 985.6.
    Another more efficient way of working this out, would be to have 616/ 5 (123.2) from silver and times that by 8 instead of having to times 616 by 8 and then dividing it again by 5, even though there was no need as it had already been done in silver.
    The change of weight if there were 6 people to severe instead of 5 would be 3.3%. I worked this out by dividing 1500g by 6 and that gives me 250g. I know that 300g is 1/5 and 250g is 1/6 so i found a common denominator between them. This makes them 6/30 and 5/30. I subtracted both of them and got the answer 1/30. Then I divided 1 by 30 and got the answer 0.033 occurring. This is a decimal so I converted it into a percentage and that gives you 3.3%.
    The change of surface area for 6 people is 3.3%. I did the same method but using the other integers.

  5. Bronze the answer is:
    The weight of the beef lasagne is 1.5 kilograms and each person would get 1/5 of the lasagne because of you do 1.5 you just need to turn it into a fraction, so it becomes,1/5

  6. Bronze: What fraction of the lasagne should each person get? What weight of lasagne should each person get?

    Each person would receive 1/5 of the lasagna and 300 grams.

    Silver: What surface area of the lasagne should each person get? Explain your workings. How many different ways (dimensions) could the lasagne be cut to give equal portions?

    The answer for sliver is 22.2 cm 2

  7. Bronze: What fraction of the lasagne should each person get? What weight of lasagne should each person get?
    Each person would get 1/5 lasagne and 300 grams.

  8. Gold:

    1) What volume of lasagne would there be in each portion?
    The volume of 1 portion is 985.6 cubed and the volume of the whole lasagne would be 4928 cubed.

  9. Bronze the answer is:
    The weight of the beef lasagne is 1.5 kilograms and each person would get 1/5 of the lasagne because of you do 1.5 you just need to turn it into a fraction, so it becomes,1/5

  10. Bronze: What fraction of the lasagne should each person get? What weight of lasagne should each person get?Each person would receive 1/5 of the lasagna and 300 grams.

    • Please could I re-write that I had not finished
      Bronze: what fraction of the lasagne should each person receive?
      What weight of the lasagne should each person get?
      Well, I know that it has to fill the hungry stomachs of five people so using that knowledge I know each person will get 1/5. I also know that the weight of the lasagne is 1.5kg and again it has to feed five people so I divided it by five and got the answer of 300g.

      • Silver: What surface area of the lasagne should each person get? Explain your workings.

        The weight is 1.5kg and the dimensions are 28L 22W 8H
        The total surface area (TSA) of a cuboid is the sum of the areas of its 6 faces, which is given by this formula
        TSA = 2 (lw + wh + hl)
        Using this formula and the provided information I got the total
        of 2032 so I divided it by 5 as it needs to feed 5 people and got the result of 406.4

        22.2 cubed is incorrect because that is a volume not a surface area.

        • Ayesha – you are absolutely right! I wonder if any of our other GD mathematicians will pick this up! I actually did mean the area on the top, but because I said “surface” area, that relates to 3d shape!

          • That is a great relief I was worried I did something wrong I kept checking my answer but nothing was wrong with it so I decided to trial it.

  11. Gold: What volume of lasagne would there be in each portion? Looking at the questions in Bronze and Silver, what would the % change in weight and surface area of each portion be if we shared between 6 people instead of 5?
    The volume of each portion of lasagne would be 985.6 cm cubed.I am not sure how to work out the rest of the question.

    • Hi Hadisa. Work out the difference between the portion weight for 5 people and 6 people. Then use the difference and the original value to calculate the % change. A tricky challlenge!

  12. GOLD : What volume of lasagna would there be in each portion? Looking at the questions in Bronze and Silver, what would the % change in weight?

    The volume of the lasangll l

      • Bronze:
        What fraction of lasagne should each person get?
        1/5
        What weight?
        300grams

        0.5 divided by 5=0.3
        0.3 times 1000 equals 300grams which is the answer to what weight should each person get.

  13. Bronze: What fraction of the lasagne should each person get? What weight of lasagne should each person get?
    Each person would get 1/5 lasagne and 300 grams.

  14. Bronze: She had 1.5kg and i needed to divide it by 5,as i did the working out I got the answer of 300g,In fractions i got 1/5 as i divided it by 5.
    this is my working out:
    1.5kg=1.5×1000=1500
    1500/5=300
    300=1/5

  15. BRONZE :
    What fraction of the lasagna should each person get? What weight of lasagna should each person get?

    Each person would receive 1/5 of the lasagna and 300 grams.

    SILVER : What surface area of the lasagne should each person get?

    The surface area a person would have is 22.2 cm 2 .

    GOLD : What volume of lasagna would there be in each portion? Looking at the questions in Bronze and Silver, what would the % change in weight?

    The volume is 985.6 cubed and the percentage of bronze would be 16.5%

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