To find the inflation rate of prom you want to start by adding the costs of each expense together under its respective year:
2009:
Limo = $180
Dress = $270
Total = $450
2019:
Limo = $216
Dress = $324
Total = $540
Next, find the consumer price increase/inflation. To do this we will take the increase of price from 2009 to 2010 and divide by the price in 2009.
2010 total: $540 - $450 (2009 total) = $90
$90/$450= 0.2 to find the percentage of inflation multiply by 100
(.02)(100)= 20%
The rate of prom inflation is 20%.
