Problem:
The Golden Gate Bridge in San Francisco was financed with construction bonds sold for $36 million in 1931. These were 40-year bonds, and the $36 million principal plus almost $40 million in interest were repaid in total in 1971. If interest was repaid as a lump sum,
Required:
Question: What interest rate was paid on the construction bonds? Please explain comprehensively and provide step by step solution.