The Scorpio Miser with its special high-efficiency engine costs more to buy than the standard Scorpio sports car  At current fuel prices, a buyer choosing the Miser would have to drive it 60, 000 miles to make up the difference in purchase price through savings on fuel
It follows that, if fuel prices fell, it would take fewer miles to reach the break-even point
The true annual rate of earnings on an interest-bearing account is the annual rate of interest less the annual rate of inflation. Consequently, if the rate of inflation drops, the rate of interest can be reduced by an equal amount without there being a change in the true rate of earnings.