Ratios are one of the most useful topics to master for UCAT Quantitative Reasoning because they appear in many different contexts.
The basic idea is simple: a ratio compares quantities.
If red and blue counters are in a ratio of 3:2, there are five equal parts in total.
If there are 25 counters altogether, one part is worth 5. That means 15 are red and 10 are blue.
A good habit is to add the ratio parts before doing anything else.
You may also need to scale ratios. If a recipe for four people uses ingredients in a certain ratio and you need to serve ten people, work out the scale factor first.
Another common question involves finding a missing amount. If A:B = 2:5 and A is 12, then one ratio part is 6. B must therefore be 30.
Ratios become harder when they are hidden inside word problems. That is why you should write the ratio clearly before calculating.
Also check whether the question asks for a part, a total or a difference. Students sometimes solve the ratio correctly but answer the wrong thing.
The fastest ratio method is usually the clearest one. Find the value of one part, then scale.
Simple, reliable and easy to check.
