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Mathematics is a subject that often comes alive when we see how it applies to real-life situations. One of the most common types of questions you’ll encounter, both in exams and in everyday life, is the percentage increase problem. Whether you’re looking at price rises in the supermarket, pay rises at work, or even the growth of a population, understanding how to calculate percentage increases is a vital skill. In this blog post, we’ll break down the process into simple steps, using a clear example to guide you through.
Understanding the Problem
Let’s start with a typical question you might see at Foundation level:
Question:
A mobile phone used to cost £120. The price increases by 15%. What is the new price of the mobile phone?
At first glance, this might seem tricky, but with a step-by-step approach, you’ll see it’s very manageable.
Step 1: Find the Percentage Increase
The first thing to do is work out how much 15% of £120 is. To do this, you need to convert the percentage into a decimal and then multiply by the original amount.
- Convert 15% to a decimal:
15% = 0.15 - Multiply by the original price: 0.15 \times £120 = £18
So, the price increases by £18.
Step 2: Add the Increase to the Original Price
Now that you know the amount of the increase, simply add it to the original price to find the new price.
- Original price: £120
- Increase: £18
- New price: £120 + £18 = £138
So, after a 15% increase, the new price of the mobile phone is £138.
Step 3: Check Your Working
It’s always a good idea to check your answer. You can do this by reversing the process. If you subtract the increase from the new price, you should get back to the original price:
- £138 - £18 = £120
This matches the original price, so your calculation is correct.
Why This Matters
Percentage increase questions are not just for exams—they’re everywhere in daily life. For example, if you see a news headline about train fares rising by 5%, or you get a letter saying your rent is going up by 2%, you’ll need to know how to work out the new amount. These skills help you make informed decisions and avoid surprises.
If you ever find yourself stuck on these types of questions, working with a Tutor for GCSE Maths In The UK can make a big difference. A good tutor can show you different methods, give you plenty of practice, and help you build your confidence with problem-solving questions.
More Examples to Practise
Let’s look at another example to reinforce the method:
Example:
A concert ticket costs £40. The price goes up by 10%. What is the new price?
- Step 1: 10% of £40 = 0.10 \times £40 = £4
- Step 2: New price = £40 + £4 = £44
Example:
A pair of trainers cost £60. The price increases by 25%. What is the new price?
- Step 1: 25% of £60 = 0.25 \times £60 = £15
- Step 2: New price = £60 + £15 = £75
Final Tips
- Always convert the percentage to a decimal before multiplying.
- Double-check your calculations, especially when adding the increase.
- Practise with different percentages and amounts to build your confidence.
By following these steps, you’ll be able to tackle any percentage increase problem with ease. Remember, practice is key—so try out a few more examples on your own, and soon you’ll be solving these questions without a second thought!
