Question 237387
"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 $0.70 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?"
:
Find the cost when she uses wood: 2 * 250 = $500 
:
Find the cost per hr using gas
{{{33000/100000}}} *.70 = $0.231 per hr
:
5 hrs a day for 120 days
120 * 5 * .231 = $138.60
:
A big savings, you can figure out how much.