A company owns and operates an electric sign that uses 300 individual lamps to display messages. The sign currently uses bulbs that cost $2.50 each and last for an average of 2 years. These lamps draw 60 watts of power each. The company is considering switching to LED bulbs that have an estimated life span of 10 years and cost $30 each. The LED bulbs only draw 7.5 watts of power for the same light levels. Replacing the lamps requires special equipment and labor that will cost $1,200 dollars. This work is performed every two years for the current lamps and at the end of 10 years for the LED lamp. The sign operates 2500 hours each year. Electricity costs $0.075/kWh. The company uses 7% as its rate of return. Assume that the maintenance protocol replaces all 300 lamps when the average lifetime is reached. Consider costs to be negative numbers and benefits as positive

a.) Compute the total annual cost of operating the sign using the 300, 60 watt lamps. DO NOT include dollar signs the answer.

b.) Compute the total annual cost of operating the sign using the 300, 7.5 watt LED lamps. DO NOT include a dollar sign in the answer. (Note: this is a cost and should be a negative value

c.) Determine the present worth of benefits by subtracting the expenses of owning and operating the LED bulbs from the conventional bulbs. (Hint: comparing the alternatives requires equal life spans. Use least common multiple of lives)

d.) Compute the benefit-cost ratio