Question 97947: Water at sea level boils at a temperature of 212 degrees Fahrenheit. For every increase in altitude of 1000 feet, the boiling point drops by 1.8 degrees. Write a linear function that gives the boiling point of water as a gunction of the altitude. What is the boiling point of water at 15,000 feet?
I have to solve this and then present it on the board during my next class and explain how I got the answer...and I have no idea what to do with this!! Please help! Thanks!!
Found 3 solutions by stanbon, jmoylan69, MathTherapy:
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! Water at sea level boils at a temperature of 212 degrees Fahrenheit. For every increase in altitude of 1000 feet, the boiling point drops by 1.8 degrees. Write a linear function that gives the boiling point of water as a gunction of the altitude. What is the boiling point of water at 15,000 feet?
Draw a chart with column heading as follows:
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ALTITUDE..........TEMP(Fahrenheit)
sea level............212 degrees
1000 ft..............212+1.8 degrees
2*1000 ft............212+1.8*2 = 215.6 degrees
3*1000 ft............212+1.8*3 = 217.4 degrees
...
...
x*1000 ft............212+1.8x
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EQUATION:
Temperature = 212+1.8x where x is the # of 1000 ft above sea level.
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Temperature at 15,000 ft.????
At 15,000 ft. x = 15
Temp = 212 + 1.8*15 = 239 degrees Fahrenheit
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Cheers,
Stan H.
Answer by jmoylan69(1)  (Show Source):
You can put this solution on YOUR website! 239 Degrees at 15000 ft is wrong. the boiling temperature drops as Altitude increases, it does not increase in boiling temp as you show.
Further you state that the boiling temperature drops by 1.8degrees for every 1000 feet. i agree. however, 1.8x15 = 27, 212-27 = 185degrees for water to boil at 15,000feet. Not 239degrees. this would be the case if it were 15,000ft BELOW sea level.
Answer by MathTherapy(10557)  (Show Source):
You can put this solution on YOUR website!
Water at sea level boils at a temperature of 212 degrees Fahrenheit. For every increase in altitude of 1000 feet, the boiling point drops by 1.8 degrees. Write a linear function that gives the boiling point of water as a gunction of the altitude. What is the boiling point of water at 15,000 feet?
I have to solve this and then present it on the board during my next class and explain how I got the answer...and I have no idea what to do with this!! Please help! Thanks!!
Slope, or drop of 1.8oF for every 1,000-foot increase: 
A temperature of 212oF at sea level gives us the point: (0, 212), which are the coordinates of the y-intercept.
y = mx + b <====== LINEAR FUNCTION
B(H) = mH + b ---- Substituting B(H) for BOILING POINT, or y, based on height, and H for x, or height
B(15,000) = - .0018(15,000) + 212 ------- Substituting 15,000 for H, - .0018 for m, and 212 for b
Boiling point of water at a height of 15,000 feet, or 
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