A word formula is an instruction explaining how to work something out.

**Example**

Here is a word formula to work out the cooking time (in minutes) for roast beef. Using this formula, the beef will come out cooked "medium".

Cooking Time in minutes = Weight in kg x 30

For how long should a 3 kg joint of beef be cooked?

**Answer**

The weight is 3 kg, so ....

Cooking Time = 3 x 30 = **90 minutes**