Improvised explosive devices (IEDs) are responsible for many deaths in times ofstrife and war. Unmanned ground vehicles (robots) can be used to disarm the IEDs andperform other tasks as well. If the robots cost $130,000 each and the militaryarms unitsigns a contract to purchase 3,500 of them now and another 6,000 one year from now, whatis the equivalent annual cost of the contract over a 8-year period at 12% per year interest?