Answer:
Approximately 6 years
Explanation:
Use Future value formula to calculate the period:
FV = Target Earning = $3 million
PV = Current Sales = $1,233,450
g = growth of sales = 16%
n = number of years = ?
FV = PV ( 1 + g )^n
$3,000,000 = $1,233,450 x ( 1 + 16% )^n
$3,000,000 / $1,233,450 = ( 1 + 0.16 )^n
2.4322 = 1.06^n
log 2.4322 = log 1.16^n
n = log 2.4322 / log 1.16
n = 5.99
n = 6 years  (Rounded off to nearest whole year)