Answer
$\$394,019$ million $> \$314,119$ million, therefore they could have bought back Manthattan
Work Step by Step
The future value of the investment can be calculated as:
$FV=PV\times (1+r)^{t}$
Here, the present value is the money invested by the Indians: $PV=\$24$
The compound rate is $r=6.3\%$
The number of periods is the years between 1626 ans 2011: $t=2011-1626=385$
Therefore the future value is:
$FV=PV\times (1+r)^{t}=24\times 1,063^{385}\approx 394,019$ million
$\$394,019$ million $> \$314,119$ million, therefore they could have bought back Manthattan
