Question 924524
 Kay wants to buy a new fireplace insert that will burn gas instead of wood.
 She normally uses two cords of wood in the winter.
 Wood costs $250/cord.
 She is interested in knowing how much she will save if she burns gas in the fireplace insert. Gas costs $ 0.91 per therm.
 One therm is 100,000 BTU.
 The fireplace insert burns 33,000 BTU per hour.
 Kay figures she will burn the fireplace 5 hours per day for 120 days.
 How much will she save in one winter if she burns gas instead of wood?
:
Burning wood costs 2 * 250 = $500
:
Burning gas requires 120 * 5 * 33000 = 19,800,000 Btu in one winter
Cost: .91 * 19800000/100000 = $180.18 
A savings of
500 - 180.18 = $319.82 savings, not to mention, it's way less messy!