- Forums
###### how can a ratio be written as a fraction (maths) GCSE

Watch

1 year ago

apparently, if there is a ratio of:

1:2 it can also be written as 1/2

and that is the same for any ratio however i'm struggling to why that is.

if A had 1 part and B had 2 parts, then surely A has 1/3 of the parts and therefore B has 2/3 of the parts as in total, there are 3 parts?

so i don't really understand why it can be written as a half.

one question i was doing in a past paper stated:

x^2 : (3x+5) = 1:2

i looked at the mark scheme and the first step was:

x^2/3x+5 = 1/2

after that, i got the answer as it resulted to be x= 5/2 or x= -1

however, the part i am struggling to understand is why did they make this ratio a fraction in the first place? how do i know when i can do it?

obviously, i don't want to get confused with ratios as there are different types of ratio questions.

thanks so much. (i'm doing GCSE btw)

1:2 it can also be written as 1/2

and that is the same for any ratio however i'm struggling to why that is.

if A had 1 part and B had 2 parts, then surely A has 1/3 of the parts and therefore B has 2/3 of the parts as in total, there are 3 parts?

so i don't really understand why it can be written as a half.

one question i was doing in a past paper stated:

x^2 : (3x+5) = 1:2

i looked at the mark scheme and the first step was:

x^2/3x+5 = 1/2

after that, i got the answer as it resulted to be x= 5/2 or x= -1

however, the part i am struggling to understand is why did they make this ratio a fraction in the first place? how do i know when i can do it?

obviously, i don't want to get confused with ratios as there are different types of ratio questions.

thanks so much. (i'm doing GCSE btw)

(edited 1 year ago)

For 1:2, it means the first part is half of the second part.

However, the first part is a third of the total, just as the second part is two thirds of the total.

So the example is correct, it just depends on what you're comparing it with (the other part or the total).

A simple example would be pocket money. Andy and Belinda get £10 and £20, so the ratio is 1;2 and Andy gets 1/2 of Belinda. However, Andy gets 1/3 of their parents money and Belinda 2/3.

However, the first part is a third of the total, just as the second part is two thirds of the total.

So the example is correct, it just depends on what you're comparing it with (the other part or the total).

A simple example would be pocket money. Andy and Belinda get £10 and £20, so the ratio is 1;2 and Andy gets 1/2 of Belinda. However, Andy gets 1/3 of their parents money and Belinda 2/3.

(edited 1 year ago)

Reply 2

1 year ago

Okay so you're not far off but that first step is tripping you up.

You are correct that that means that A has 1/3 of the parts total, but A/B = 1/2

If you take the total parts to be u

A = 1/3 U

B = 2/3 U

A/B = (1/3u)/(2/3u)= 1/2

Alternatively, As mqb2766 said above, B is twice of A so B/A = 1/2 like how 8/4 = 1/2

You are correct that that means that A has 1/3 of the parts total, but A/B = 1/2

If you take the total parts to be u

A = 1/3 U

B = 2/3 U

A/B = (1/3u)/(2/3u)= 1/2

Alternatively, As mqb2766 said above, B is twice of A so B/A = 1/2 like how 8/4 = 1/2

- 2022 Edexcel Maths GCSE (Higher) Checklist
- gcse maths
- Help with this gcse maths question?
- The number 153
- Maths help - Vectors
- BKSB maths assessment
- ratio maths question
- What topics are NOT in the non calculator paper in GCSE maths?
- maths bridge between GCSE and a level question
- Maths ratio question
- Buffer calculation help
- Extremely Hard GCSE Maths Question
- The Hard Grade 9 Questions Thread 2019
- Edexcel GCSE Foundation tier Maths Paper 1 1F (1MA1) - 19th May 2023 [Exam Chat]
- Maths Question Help
- Maths
- Answer
- Topics?
- Edexcel GCSE Mathematics Paper 1 (Non-Calculator) Higher 1MA1 1H - 20 May 2022 [Chat]
- Rearraging the capacitor charge equation for time

- Official: University of Bristol A100 2024 Entry Applicants
- What Music do you listen to? ♥
- Motivational GYG Journey (2023-2024)
- help idk how to use this app xoxox
- Sutton Trust US programme
- Serena La Sorcière and the Pursuit of Greater Knowledge
- Gcse help
- City University London - Investment and Financial Risk Management BSc
- Ucat help!
- PiXL A Level Biology Resources
- difficulty finding a job?
- Therapeutic Times with Persephone and Pals!
- KCL Dentistry 2024 Entry
- lia's path to becoming an academic weapon!
- gyg: My Villain Origin Story 💣👽🙌🧠
- Glasgow Dentistry 2024 Entry
- Would your essay be less 'unique' if it was at the bottom of the pile?
- Gcse help
- City of London Academies Highgate Hill (Islington) and Shoreditch Park (Hackney)
- Pupillage Application 2023-2024

- Can you become a Pilot with BTEC qualifications?
- Glasgow School of Art vs Newcastle University
- Official Lancaster University Offer Holders Thread for 2024 entry
- Oxford MSc in Advanced Computer Science 2024 Entry
- JP Morgan Technology Degree Apprenticeship 2024
- Will I get a TN to Kirkland & Ellis
- 2024-2025 Oxford MSc in Social Data Science
- Idea silver badge (Gamer) Part 1
- UCL Medicine A100 2024
- go big or go home: my guide to conquering gcse's ☆
- Mst in English (all streams)
- Edinburgh offers 2024
- [Official thread] Durham University 2024 Applicants
- My GCSE journey!! 🦞
- Spending too long revising to get A*s at A Level
- UKChO 2024
- KCL neuroscience and psychology 2024
- Dundee Dentistry 2024 Entry
- Official Veterinary Medicine Applicants thread 2024 entry
- Lloyds Banking Group 2024 Graduate Scheme

- GCSE Mathematics Study Group 2023-2024
- A-level Mathematics Study Group 2023-2024
- Mock set 4 paper 2 q14 a level maths (4 distinct points)
- UKMT Intermediate Math Challenge 2024 - Discussion
- Help with complex summation further maths a levels
- Could I have some help with this suvat question?
- MAT practice
- Alevel Maths Question
- weird cosine question
- Series function not differentiable at a point

- hyperbolic function catenary problem
- can anyone answer this A level vectors question (very challenging)
- STEP foundation module help pls
- Ukmt IMC 2024
- ukmt imc
- This maths question is driving me crazy
- Maths Mechanics
- Confused on surds question
- HNC MATHS A2 Task 3 (Radio Transmitters)
- Senior Maths Challenge 2023

- GCSE Mathematics Study Group 2023-2024
- A-level Mathematics Study Group 2023-2024
- Mock set 4 paper 2 q14 a level maths (4 distinct points)
- UKMT Intermediate Math Challenge 2024 - Discussion
- Help with complex summation further maths a levels
- Could I have some help with this suvat question?
- MAT practice
- Alevel Maths Question
- weird cosine question
- Series function not differentiable at a point

- hyperbolic function catenary problem
- can anyone answer this A level vectors question (very challenging)
- STEP foundation module help pls
- Ukmt IMC 2024
- ukmt imc
- This maths question is driving me crazy
- Maths Mechanics
- Confused on surds question
- HNC MATHS A2 Task 3 (Radio Transmitters)
- Senior Maths Challenge 2023

The Student Room and The Uni Guide are both part of The Student Room Group.

© Copyright The Student Room 2024 all rights reserved

The Student Room and The Uni Guide are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: Imperial House, 2nd Floor, 40-42 Queens Road, Brighton, East Sussex, BN1 3XB