13,500 at 5.2 for 8 years compounded semi-annually.
Total = Principal * (1 + rate/n) ^n * years
where "n" = number of compounding periods per year.
Total = 13,500 * (1 + .052 / 2) ^ 2 * 8
Total = 13,500 * (1.026) ^ 16
Total = 13,500 * 1.5078487226
Total = 20,355.96
Source
1728.com/compint3.htm