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Linear and Quadratics CD - Example

Body Mass Index is a simple calculation to show a person is healthy or not. Here is the formula for calculating BMI.

BMI = Weight/(height squared)

If BMI is below 18.5, this suggests that your weight may be too low. If BMI is 25.0 or more, this means you might be overweight. How to represent the healthy range by using linear inequality symbols (>, <, , , )?


If an adult is double height and double weight of a child, are their BMI the same? Explain your answer.



How to eat correctly is very important for keeping a healthy BMI. Eat the right amount of calories for how active you are, so that you balance the energy you consume with the energy you use. It is recommended that men have around 2,500 calories a day. Women should have around 2,000 calories a day.

We all need some fat in our diet. The average man should have no more than 30g saturated fat (included in hard cheese, cakes, biscuits, sausages, cream, butter, lard, pies) a day. The average woman should have no more than 20g saturated fat a day, and children should have less than adults.


More than 1.5g of salt (means 3.75g of sodium) per 100g means the food is high in salt. Adults and children over 11 should eat no more than 6g of salt (about a teaspoonful) a day. Younger children should have even less.

Please read the following food labels, then give a suggestion about one-day menu for a man.

Here is an answer.

For this menu, you could notice that, it's easily to eat too much saturated fat if you eat too much beef or sausage.

Sugar from the food may be not enough, you need to add some sugar when you are cooking, or you could eat some chocolate, then you could get enough sugar and calories.

If you are still hungry, you could eat more potatos or broccoli, but don't fry them, or the fat might be too much. Don't add too much salt, as there is enough in the canned tuna or sausage.