In order to create a pizza for 6 people, 300 grams of cheese must be used. How much cheese would be necessary to make a pizza that would have sufficient cheese for 8 people?
In order to answer this question there are a number of different steps that need to be completed. The best way to work out this question is to calculate the amount of cheese each serving is getting. Once we have this we will have to correct ratio, here being 1:50. The 1 on the left side of the ratio represents the number of people and the 50 represents the amount of cheese. All we now need to do is multiply each side of the ratio by the number desired, in this case being 8, to get the correct answer.
Using fractions and decimals is a very useful way of evaluating ratios in numerical tests. This is because in a sense, a ratio is merely a different way expressing a fraction. For example we think of one quarter as ¼. This could be represented easily as a fraction as 0.25 but also in terms of ratios as 1:4. This is very important as when you are working out future calculations it is easier to simply do the same to both sides of the ratio in order to arrive at the correct answer.
Learning how to calculate ratios from other number data is also very important to the understanding of ratios. For example:
There a 7 shirts and 4 pairs of trousers in my cupboard. Calculate the ratio of shirts to clothes.
Here you are asked to perform two sets of calculations; first of all the total number of cloths (7+4=11) and then to work out the ratio of shirts to cloths. In this example, as there are seven shirts out of a total of 11 items of clothing the answer is 7:11.
When calculating a ratio there is an important point to bear in mind; are you being asked about the ratio units or are you being asked about the relationship between the two sides of the ratio. In the above example, we are asked to work out the relationship to the total number of clothes. To do this, we need to work out the total number of items in the closet. This is done by calculating the ratio units, 7+4. We then use that figure to craft the ratio. If however, you are asked to show the relationship between the two items we don’t need to know the total number of clothes and it is simply represented as 7:4 shirts: trousers.
When working with ratios it is very important to remember that it is always the item in the question that comes first is the beginning of the ratio, seven shirts to 11 items of clothing, NOT the other way round. If this ratio is expressed in the opposite direction it would mean that there are 11 shirts to 7 items of clothing, obviously nonsensical and definitely wrong.
We have come to a basic understanding of how ratios work and gone through a few examples that you could face as part of a numerical reasoning test. Practising these questions and gaining confidence to calculate them in a short amount of time is the only key to success. Here at JobTestPrep, we have an extensive range of practise numerical reasoning tests that you can take under timed conditions with or without a calculator or as a practice session.