The Time $t$ In Years for an Amount Increasing at a Rate

Multiple Choice

The time $t$ in years for an amount increasing at a rate $r$ (in decimal form) to double is given by $t(r) =\frac{\ln 2}{\ln (1+r) }$ . This is called "doubling time." How long will it take for prices in the economy to double at a $4 \%$ annual inflation rate? Round to the nearest year.

A) $14 \mathrm{yr}$
B) $18 \mathrm{yr}$
C) $28 \mathrm{yr}$
D) $23 \mathrm{yr}$