How to solve rates of change questions?

If the question is about something losing value, for example a cars value depreciates at a rate of 30% a year after 4 years how much will the car be worth? You are also given that at year 0 it was worth £10,000. Therefore in order to solve it you can either solve it year by year with the percentage change converted into a decimal of 0.7. This is because 1 would represent no percentage change so 100%. A 30% depreciation would therefore only represent 70% of the original value and converting 70% to a decimal gives you 0.7. So for example: Year 1= 10,000 x 0.7 = 7000 Year 2 = 7000 x 0.7 = 4900 Year 3 = 4900 x 0.7 = 3430 Year 4 = 3430 x 0.7 = 2401 An alternative method (and a quicker one) would be to calculate the value of the car after 4 years straight away. For this you take the original value (£10,000) and times it by 0.7^4. You times 0.7 by the power of 4 as this is the 4 years that the car is losing value. 10,000 x 0.7^4 = 2401 Both these methods give the same answer.

EW
Answered by Emma W. Maths tutor

5126 Views

See similar Maths GCSE tutors

Related Maths GCSE answers

All answers ▸

Make "a" the subject of the following equation: 2b = (3a+4)/(c-a)


How to solve an equation when the variable is in the denominator?


To make 12 cakes you need 100g of butter, 6 eggs, and 40g of sugar. How many cakes can you make with 450g of butter, 15 eggs, and 110g of sugar?


How to solve the simultaneous equations 3x+2y=7 and 5x+y=14


We're here to help

contact us iconContact ustelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

© MyTutorWeb Ltd 2013–2025

Terms & Conditions|Privacy Policy
Cookie Preferences