Answer:
$ 10,234.80 should be invested.
Explanation:
Since, the amount formula in compound interest,

Where, P is the principal amount,
r is the annual rate,
n is the number of period in a year,
t is the number of years,
Here, A = $ 26,000, r = 12% = 0.12, t = 8 years,
n = 2 ( number of semiannual in a year = 2 ),
By substituting the values,



Hence, $ 10,234.80 should be invested.