Answer:
weighted expenditures   54,350
avoidable interest        6,522
capitalized interest       6,522
interest revenue          2,725
Total Interest expense     12,310‬     Â
Explanation:
217,400 paid to Misk and capitalized until Nov 1st:
August, September, October: 3 months
217,400 x 3/12 = 54,350 weighted expenditures
We apply to this the specific borrowing rate:
54,350 x 12% = 6,522
Interest revenue
amount invested: 326,400 - 217,400 = 109,000
at 10% for a period of 3 month:
109,000 x 10% x 3/12 = 2,725
Interest expense:
326,400 x 12% x    5/12   =  16,320
 31,400 x  8%  x full-year  =   2,512
avoidable interest         (6,522) Â
Total Interest expense      12,310‬