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Question 902222: At sea level, the boiling point of water is 100°C. At an altitude of 5 km, the boiling point of water is 82.5°C.
Write a linear function for the boiling point of water y in terms of the altitude above sea level x.
Found 2 solutions by richwmiller, Theo:
Answer by richwmiller(17219)   (Show Source):
You can put this solution on YOUR website! use the points as (0,100) and (5,82.5)
(0,100),(5,82.5)
0,100,5,82.5
m=-17.5/5=-3.5
b=-1*-17.5/5*0+1*100=100
y= -17.5/5x+100
y= -3.5x+100
Answer by Theo(13342)  (Show Source):
You can put this solution on YOUR website! at sea level the boiling point is 100 degrees centigrade.
at 5km above sea level, the boiling point of water is 82.5 degrees centigrade.
let x = the number of km above sea level.
when x = 0, the boiling point is 100 degrees centigrade.
when x = 5 km, the boiling point is 82.5 degrees centigrade.
the average change in boiling point is equal to (82.5 - 100) / 5 which is equal to -17.5 / 5 which is equal to -3.5 degrees centigrade per kilometer.
the formula becomes:
y = -3.5*x + 100
when x = 0, y = 100
when x = 5, y = 5*-3.5 = -17.5 + 100 = 82.5 degrees centigrade.
the graph looks like this:
the slope of the line becomes the change in the value of y divided by the change in the value of x.
the change in the value of y is the change in the boiling point of water.
the change in the value of x is the change in the number of kilometers above sea level.
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