Answer
Saving on fifteenth day $a_{15}$ = 16384
Work Step by Step
Given
Common ratio (r) = 2 as saving be twice of day before
Saving on first day$a_{1}$ = 1
By formula $a_{n}$ =$a_{1} r^{n - 1}$
Saving on fifteenth day$a_{15}$ = $a_{1} r^{15 - 1}$
= $1\times 2^{14}$
= 16384
