13. A company is planning to replace a manual packaging system by a robotic system. The robot is priced at $120,000. The required accessories cost $15,000. The annual maintenance, software upgrade, and operation cost of robotic system on a double-shift basis is $15,000. The company is eligible for a $20,000 tax credit from the government under its technology investment program. The robot will replace three operators. The hourly rate of an operator is $24 including fringe benefits. There is no increase in production rate. Determine the payback period for double-shift operations