Q. The population of a town in the year 1990 was 15600.

The population of 15600 was 2.5% less than the population in the year 1980.

Calculate the population in the year 1980.

//The answer is 16000 but when I did it I got 15990.

I did (15600*102.5)/100

The right method is 15600 * (100/100-2.5)

CAN someone tell me why my method is wrong//

The population of 15600 was 2.5% less than the population in the year 1980.

Calculate the population in the year 1980.

//The answer is 16000 but when I did it I got 15990.

I did (15600*102.5)/100

The right method is 15600 * (100/100-2.5)

CAN someone tell me why my method is wrong//

Original post by 123IGSTUDENT

Q. The population of a town in the year 1990 was 15600.

The population of 15600 was 2.5% less than the population in the year 1980.

Calculate the population in the year 1980.

//The answer is 16000 but when I did it I got 15990.

I did (15600*102.5)/100

The right method is 15600 * (100/100-2.5)

CAN someone tell me why my method is wrong//

The population of 15600 was 2.5% less than the population in the year 1980.

Calculate the population in the year 1980.

//The answer is 16000 but when I did it I got 15990.

I did (15600*102.5)/100

The right method is 15600 * (100/100-2.5)

CAN someone tell me why my method is wrong//

Your method takes 2.5% of 15600 not the original population in 1980.

To revert back to an original population divide by (100-percentage change) then times that answer by 100

- What types of questions can appear with percentage calculations?
- Maths percentages
- Modelling the state – is it time for the OBR to have control over fiscal policy?
- John Locke Essay Competition 2023 Shortlist Percentage
- Edexcel igcse biology 1B
- Can someone help me on this biology question?
- iGCSE Edexcel Biology Paper 2 2024
- economics aqa grade boundaries
- iGCSE Edexcel Biology Paper 1BR 2024
- Calculating averages with or without anomalies?
- Edexcel A Level Economics A Paper 2 (9ECO 02) - 20th May 2024 [Exam Chat]
- Edexcel igcse biology
- AQA GCSE Business Paper 1 (8132/1) - 14th May 2024 [Exam Chat]
- SQA grade boundaries
- Eduqas A Level Business Paper 1 - 14th May 2024 [EXAM CHAT]
- GCSE results day scares me
- Why does potential difference increase when resistance increases?
- urgent biology help
- In v=ab^t. What does b represent. Logb is the gradient I think but what is b. Thanks
- le chapeliers principle, exo and endo?????

Last reply 1 week ago

STEP 2 in 2024: Sharing Your Story! [PLUS WITH SOME SOLUTIONS AND PREDICTION]Maths

18

80

Last reply 1 week ago

A level maths paper 2 (pure and statistics) and paper 3 (pure and mechanics) ocrMaths

4

6

Last reply 1 week ago

STEP 2 in 2024: Sharing Your Story! [PLUS WITH SOME SOLUTIONS AND PREDICTION]Maths

18

80

Last reply 1 week ago

A level maths paper 2 (pure and statistics) and paper 3 (pure and mechanics) ocrMaths

4

6