Equity =87,000*39 = 3,393,000
Debt issue 1 = 230,000*1.031 = 237,130
Debt issue 2 = 5000*887 = 4,435,000
Total debt = 4,435,000+237,130 = 4,672,130
Total capital = 4,672,130 + 3,393,000 = 8,065,130
Capital structure weight of the firm's debt = 4,672,130/8,065,130 = 0.5793