Disclaimer: These are hypothetical scenarios, not real.
In 1995, a Ford Mondeo costs £13,695 for a basic model.
In 2017, a Ford Mondeo costs £18,550 for a basic model.
To work out how much the price has gone up in those years, I did:
13,695/18,550 = 0.7383
18,550/13,695 = 1.3545
1.3545 / 100 = 35.45
The car has gone up by 35.45%.
Am I correct, or is my math wrong with working out a cost increase?
Second example:
In 2017, a Mercedes-Benz C-Class cost £24,650 for a basic model
In 1988, a Mercedes-Benz 190 cost £8,995 for a basic model.
These are my calculations:
24,650/8,995 = 2.7404
8,995/24,650 = 0.3649
The car has gone up by 174.04% in between.
Is my math correct, or do I need to correct my calculations for working out percentage increase or decrease?
For calculating percentage increase or decrease the formula is $$ \frac{y-x}{x} \times 100 $$ where y is the new price and x is the old price. For your sums it would be $ \frac{18,550 - 13,695}{13,695} \times 100 = 35.45 \% $ and $\frac{24,650 - 8,995}{8,995} \times 100 = 174.04 \%$
There are also a lot of online tools you can use for this purpose like this