In the ENGR 10 lab (E391), there are 75 long light bulbs (P=100 W) and 6 regular bulbs (P=60 W). How much energy is consumed lighting the lab during the 3 lab periods (9hours). Calculate the amount of energy saved if all bulbs are replaced by CFL (spiral) bulbs (P=25W). Calculate the amount of natural gas (ft3) needed to provide the energy to keep the lights (long + regular) in the E391 lab on overnight for a month (10 hours per day for 30 days)? In other words, how much extra energy (in terms of cubic feet of natural gas) does the school have to purchase when we don't turn off the lights in a lab. (Note: you'll have to look up the energy in one ft3 of natural gas.