Learn How to Work Out Ratios in Numerical Reasoning Tests

If you’ve been asked to take a numerical reasoning test, chances are likely that you’ll need to know how to work out ratios. Similar to fractions, numerical ratios represent relationships between two values, and they’re used both in graduate-level mathematics and in everyday situations. Below, we’ll provide a short review on how to calculate ratios and then prepare with a few sample questions.

What Are Numerical Ratios?

We use numerical ratios to represent the relationship between two values. Whether we are comparing a part to a whole, a whole to a part, or a part to a part, we can use numerical ratios. For example, you might represent the following using ratios:

• 3:5- For every three tomatoes, there are five vegetables in total
• 5:3- In every group of five vegetables, there are three tomatoes
• 1:1- There is one tomatoes for every pepper

We write ratios in three different ways, listed as follows:

• 3:5
• 3/5
• 3 to 5

Regardless of whether you write the ratio using a colon, fraction bar, or the word “to,” make sure that you always simplify the expression. 2:2 should be written as 1:1, and 3:6 should be written as 1:2.

Ratio Direction: Order of Reading Ratios

When you’re working out a ratio, make sure you read it from left to right and not from right to left. For instance, if I were to say that there were 2 boys in the class for every 3 girls, I would have to write that as 2/3, 2:3, or 2 to 3.

If I were to say 3/2, the meaning of the ratio would change. No longer would it mean that there are 2 boys to every 3 girls, but rather 3 boys to every 2 girls. Like fractions, ratios have a rigid structure.

How to Calculate Ratios on Psychometric Exams:

There are a few different ways of calculating ratios on a pre-employment assessment. On some questions, you’ll be given different values and asked to write the ratio. On other questions, you’ll be given the ratio and asked to find a value using that ratio. If you’re a job-seeker, make sure to check out the questions and answer explanations below to learn more.

Ratio Tips:

1. Units: You can’t write one ratio using two different units. If you’re given minutes and hours, make sure you write both values in terms of minutes or hours, but not both.
2. Order: If you’re given multiple ratios, make sure you keep your values consistent. For instance, if you have 15 miles/4 hours and 12 miles/5 hours, make sure that distance stays on the left in both ratios and time stays on the right.
3. Cross-Multiply: If you’re given two ratios and asked to find a missing value, set the missing value as X and cross-multiply.

Helpful Video:

Still worried about your ratios test? Watch the tutorial below to learn more.

Online Ratio Practice:

Make sure to check out our sample questions and answers before heading out to the assessment center for your aptitude test.

Sample Screening Questions:

1. Lindsay has pens and pencils in a jar on her desk. If she has a total of 15 pens and pencils, and the ratio of pens to pencils is 2:1, what’s the difference between the total number of pens and pencils?
   1. 1
   2. 5
   3. 2
   4. 10
2. Tommy is making dinner, but since he only wants to cook for two, he’s cutting the recipe in half. If the recipe calls for 2 tablespoons of oil for 6 servings, but Tommy only wants to make 2 servings, how much oil should he use?
   1. 1 T.
   2. 2 T.
   3. 2/3 T.
   4. ½ T.

Explained Answers:

1. Answer: B
   If the ratio of pens to pencils is 2:1, there must be 10 pens and 5 pencils. Therefore, the difference between the two is 5.
2. Answer: C
   If Tommy needs 2 T. of oil to make 6 servings, we can write the ratio as 2:6 or 1:3. If we only need 2 servings, we can write the second ratio as x:2. By cross multiplying, as you see below, you find that x=2/3.

   1/3 = x/2

   2=3x

   2/3 =x