Answer:
11.6%
Explanation:
the total cost of calling the bonds = ($50 + $10) x ($5,000,000 / $1,000) = $300,000
the bonds' coupon payment = $5,000,000 x 12% = $600,000
the company should call the bonds only if it is profitable, and the savings are equal or higher than the costs
cost of calling the bonds ≤ number of years x (coupon - rate) x total bonds
$300,000 = 15 x [$600,000 - (rate x $5,000,000)]
$300,000 / 15 = $600,000 - (rate x $5,000,000)
$20,000 = $600,000 - (rate x $5,000,000)
rate x $5,000,000 = $580,000
rate = $580,000 / $5,000,000 = 0.116 = 11.6%