Final answer:
The maximum cost of a CFL that would make the total cost equal to that of an incandescent bulb can be calculated by comparing the electricity cost and investment cost for both bulbs. Therefore the correct answer is near option d. $2.00.
Step-by-step explanation:
The maximum cost of a CFL such that the total cost (investment plus operating) would be the same for both CFL and incandescent 60-W bulbs can be calculated by comparing the electricity cost and the investment cost between the two bulbs.
For the incandescent bulb, the electricity cost for 1000 hours is $7.20. Since the CFL uses only 15 W and not 60 W, the electricity cost will be $7.20/4 = $1.80.
The CFL will last 10 times longer than the incandescent, so the investment cost will be 1/10 of the bulb cost, which is 0.1($1.50) = $0.15.
Therefore, the total cost for the CFL will be $1.80 + $0.15 = $1.95 for 1000 hours.