Ratios and Proportions - Numerical Reasoning

Often ratios and proportions problems are key instrument measures incorporated into aptitude tests by occupational psychologists to measure quantitative aptitude of individuals. Most people understand these concepts at basic level however when it comes to executing such calculations in numerical reasoning tests many candidates don’t know where to begin. For that reason standalone knowledge of such concepts itself is not sufficient but rather you have to acquire experience of solving these problems in context of psychometric testing. Hence, investing time to improve in such areas of arithmetic is valuable asset not only to success in your tests but also to accomplishments in your daily life as you may need to deal with wide range of similar challenges in your daily routine. Read the below paragraphs to find out how to work out problems related to ratios and proportions effectively in scope of psychometric tests.Alternatively, you can refer to practice test guide for more topics.


How to calculate ratios
When it comes to carrying out and performing effective calculations related to these concepts in numerical reasoning ability tests there are few things you have to keep in your mind. Below we will demonstrate how to evaluate ratios quickly and almost instantly. Consider the table and question below.

ratios_and_proportions_numrical_reasoning

What is the ratio of bottle E to bottle D of vine?

To quickly calculate the above, divide in your calculator 1,500 by 1,200. If you are performing this calculation in ‘Stats’ mode then you would get 1.25. Remember, you don’t have to convert 1.25 to fraction mentally in your head which may take away from you valuable seconds but rather use your calculator to convert the above by pressing SD. SD in ‘Stats’ mode converts decimal into fraction. However, if you would perform the above calculation 1,500 / 1,200 in ‘Math’ mode you would get ratio in its lowest form instantly; that is 5/4. Now, the question may arise how to set the calculator into ‘Maths’ or ‘Stats’ mode? The best advice we can give here is to follow guide that comes along with your calculator, however, for those of you who use Casio fx-85ES press mode and choose 1: COMP (Math) or 2: STAT mode.


How to work out proportions
Now consider second question which will demonstrate and put into practice the above techniques on similar example.

If it is recommended to mix squash and water in the ratio of 2:5, then what would be the approximate fraction of water and squash left if 490ml drink was made from bottle B of squash and bottle D of water?

If you don’t know how to formulate necessary equation then see direct proportions guide which breaks down necessary steps to solve related questions. However, to tackle the above proportional problem at numerical reasoning test effectively make as many mental calculations as you can providing that these can be worked out quicker in your head than in your calculator. In our case mentally add 2 with 5 and divide 490 by 7 and perform necessary multiplications of 2 with 70 and 5 with 70 in your head. Then subtract values and you will get the ratio of water to squash that is left as 550: 180. If you have your calculator set up in ‘Stats’ mode and you will input 55/18 then you will get 3.05 and you can conclude that this approximately equals to 3:1. However, if you calculator will be set up in ‘Math’ mode you get 55/18. Remember, to convert this into decimal press SD to get 3.05. To be quick in these calculations you have to train your mental aptitude ability on daily bases.