Succeed with maths – Part 2

# 3.1 Formulas in cooking

The time to cook a fresh chicken depends on its mass (commonly called weight in everyday language), as given by the following formula:

Roughly how long will a chicken with a mass of 2.2 kg take to cook?

To use the formula, you need to substitute the mass of the chicken into the right side of the formula and then work out the resulting calculation. However, the formula asks for the mass in grams, so the first step is to convert 2.2 kilograms (kg) into grams (g).

Since there are 1000 g in 1 kg,

Substituting 2200 for the ‘mass in grams’ in the formula gives:

Following the BEDMAS rules, the multiplication and division must be carried out first, which gives:

(If you are unsure about what BEDMAS is, you can find out more in Succeed with maths – part 1 .)

So the cooking time would be about 125 minutes, or 2 hours and 5 minutes.

Now use the same formula for a different sized chicken in the next activity. Remember to check carefully what units of mass are required.

## Activity 6 A smaller bird

Allow approximately 5 minutes

How long would it take to cook a chicken with a mass of 1.6 kg?

## Answer

First, convert 1.6 kg into grams, since the formula requires the mass in grams.

So,

Substituting this value into the formula gives:

The chicken would take about 95 minutes, or 1 hour and 35 minutes to cook.

The next example is an application from health care.

OpenLearn - Succeed with maths – Part 2
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