An electric device delivers a current of [tex]$15.0 A$[/tex] for 30 seconds. How many electrons flow through it?
Answer (1)
Calculate the Consumer Price Index (CPI) for year XXX1: CP I XXX 1 = 3750 .
Calculate the Consumer Price Index (CPI) for year XXX2: CP I XXX 2 = 4040 .
Calculate the inflation rate: I n f l a t i o n R a t e = 3750 4040 − 3750 × 100 = 7.7333... .
Round the inflation rate to the nearest tenth of a percent: 7.7% .
Explanation
Understanding the Problem We are given the Consumer Price Index (CPI) for two years, XXX1 and XXX2, across various categories. Our goal is to calculate the inflation rate between these two years. The inflation rate measures the percentage change in the CPI from one period to another.
Calculating CPI for Each Year First, we need to calculate the CPI for each year by summing the CPI values for all categories. For year XXX1, we have:
CP I XXX 1 = 1300 + 400 + 280 + 470 + 640 + 210 + 150 + 300 = 3750
For year XXX2, we have:
CP I XXX 2 = 1350 + 430 + 300 + 590 + 720 + 200 + 140 + 310 = 4040
Calculating the Inflation Rate Now that we have the CPI for both years, we can calculate the inflation rate using the following formula:
I n f l a t i o n R a t e = CP I XXX 1 CP I XXX 2 − CP I XXX 1 × 100
Plugging in the values we calculated:
I n f l a t i o n R a t e = 3750 4040 − 3750 × 100 = 3750 290 × 100 = 0.077333 × 100 = 7.7333...
Rounding the Result Finally, we need to round the inflation rate to the nearest tenth of a percent. So, 7.7333... becomes 7.7%.
Final Answer Therefore, the inflation rate from year XXX1 to year XXX2 is 7.7%.
Examples
Understanding inflation rates is crucial for making informed financial decisions. For example, if you're considering investing in a bond with a 5% return, but the inflation rate is 3%, your real return is only 2%. This calculation helps you assess the true value of your investments and savings over time, ensuring your money grows in real terms.
