An engineer is working on the layout of a new research and experimentation facility. Two plant operators will be required. If, however, an additional $100, 000 worth of instrumentation and remote controls were added, the plant could be run by a single operator. The total before-tax cost of each plant operator is projected to be $35, 000 per year. The instrumentation and controls be depreciated at a CCA rate of 20%. If this corporation (the corporate tax rate is 34%) invests the additional instrumentation and controls, how long will it take for present worth of the after-tax benefits to equal the present worth of costs? Use MARR of 10%.