Solve the Problem $\mathrm { P } ( \mathrm { t } )$

Multiple Choice

Solve the problem.
-A certain country's population $\mathrm { P } ( \mathrm { t } )$ , in millions, t years after 1980 can be approximated by $\mathrm { P } ( \mathrm { t } ) = 2.495 ( 1.018 ) ^ { \mathrm { t } } \text {. }$ Find the doubling time. Round your answer to the nearest tenth.

A) $61.6 \mathrm { yr }$
B) $38.9 \mathrm { yr }$
C) $77.7 \mathrm { yr }$
D) $51.2 \mathrm { yr }$