Valerie's initial purchasing power is 200 novels, but it decreases with inflation while the real interest rate falls proportionally.
How is that so?
Given:
- Initial deposit = $2,000
- Price of a mystery novel = $10.00
Calculation:
Initial purchasing power = Initial deposit / Price of a novel = $2,000 / $10.00 = 200 mystery novels
Purchasing Power after One Year
For each inflation rate, we need to:
- Calculate the new price of a mystery novel after inflation.
- Calculate the new purchasing power of Valerie's deposit after one year.
- Calculate the real interest rate.
Inflation Rate = 0%
New Price: $10.00 * (1 + 0%) = $10.00
Purchasing Power: $2,200 / $10.00 = 220 mystery novels
Real Interest Rate: 10% - 0% = 10%
Inflation Rate = 10%
New Price: $10.00 * (1 + 10%) = $11.00
Purchasing Power: $2,200 / $11.00 = 200 mystery novels
Real Interest Rate: 10% - 10% = 0%
Inflation Rate = 13%
New Price: $10.00 * (1 + 13%) = $11.30
Purchasing Power: $2,260 / $11.30 = 194.69 mystery novels
Real Interest Rate: 10% - 13% = -3%
As the inflation rate increases, the real interest rate decreases. This means that the purchasing power of Valerie's deposit declines even though it is earning interest.