From angle bisector theorem, we know that:

Moreover:

so:

and
We are given with the following:
Effective annual interest, i = 0.0425
Future worth, F = $25000
Number of years, n = 18
We use the formula to solve for the present worth of the money:
P = F / (1 + i)^n
P = 25000 / (1 + 0.0425)^18
P = 11818.73
The closest answer is:
<span>b.
$11,820</span>
400, if you can buy 4 tickets for $6 you can buy 400 for $600