Understanding Variation and How to Solve It in JAMB Mathematics 2025

Variation is one of those topics JAMB quietly brings almost every year. It’s usually just one or two questions, but they are often very easy—if you know what to do. Many students either overthink it or forget the basic steps. But once you understand how variation works, it’s one of the simplest areas to score marks in JAMB Mathematics.

This guide will explain variation in a very simple way, how to spot it, and how to solve it quickly.

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What Does Variation Really Mean?

Variation simply means how one quantity changes in relation to another. In JAMB, you’ll see words like “varies directly”, “varies inversely”, or “joint variation.” All these mean that a relationship exists between two or more things.

For example:

• If the more hours you work, the more money you earn, that’s direct variation.
• If the more people share food, the smaller each person’s portion becomes, that’s inverse variation.
• If one thing depends on two or more things, it could be joint or partial variation.

Start with Direct Variation

If the question says: “y varies directly as x”, you simply write:

y = kx

Where k is a constant. You’ll be given values to find k, then use it to solve the rest of the question.

Let’s say: y varies directly as x, and y = 10 when x = 2.

That gives us: 10 = k × 2 → k = 5

Now you can write: y = 5x

If you’re asked to find y when x = 7: y = 5 × 7 = 35

It’s that simple.

Inverse Variation Is Just the Opposite

If a question says: “y varies inversely as x”, write:

y = k / x

Same process: find k with the values given, then plug in the one you’re asked to find.

Example: y varies inversely as x, and y = 4 when x = 3

That gives: 4 = k / 3 → k = 12

So: y = 12 / x

If x = 6, then: y = 12 / 6 = 2

Just remember that in inverse variation, as one increases, the other decreases.

Joint Variation Looks Hard but Isn’t

Sometimes, JAMB says: “y varies directly as x and inversely as z”
That simply becomes:

y = kx / z

As long as you understand the pattern, you can solve it like the others.

Final Words

The trick to solving variation questions in JAMB is not rushing. Read the question slowly, know what type of variation you’re dealing with, and write the correct formula.

After that, it’s just simple substitution. No need to cram—just practice using past questions, and you’ll begin to recognize the style immediately.

Variation is one of those topics where every mark is within reach. With steady practice, you’ll never be confused by it again in the exam.