SOLUTION: Hey how would you set up this equation? Istas rides her bicycle down a hill. For every kilometer that she rides, her altitude changes by -9m. What is Istas�s altitude relative to

Question 176432: Hey how would you set up this equation?
Istas rides her bicycle down a hill. For every kilometer that she rides, her altitude changes by -9m. What is Istas�s altitude relative to her starting point after she rides 7km?
I�m thinking it would be (-9)(7)
Since the rider is going down hill, then would that make the distance a negative number or positive number?
A) 16m
B) -16m
C) 63m
D) -63m

Found 2 solutions by solver91311, MathTherapy:
Answer by solver91311(24713) (Show Source): You can put this solution on YOUR website!
It has to be a negative number because she is going downhill and the question asks for her altitude relative to her starting point.
Answer by MathTherapy(10556) (Show Source): You can put this solution on YOUR website!
Hey how would you set up this equation?
Istas rides her bicycle down a hill. For every kilometer that she rides, her altitude changes by -9m. What is Istas�s altitude relative to her starting point after she rides 7km?
I�m thinking it would be (-9)(7)
Since the rider is going down hill, then would that make the distance a negative number or positive number?
A) 16m
B) -16m
C) 63m
D) -63m

For every kilometer (1,000 m) that she travels downhill, her altitude decreases by 9 m. Therefore, when she travels 7 km (7,000 m) downhill, her altitude will be decreased by 63 m.
Her starting altitude, obviously, has to be greater than 63 m. So, let's say her starting point, or original altitude, or highest point on that hill is "s,"m then her altitude, after going 7 km downhill would be (s - 63)m.
The distance she has traveled is not negative. Distances are never negative. That's impossible. The negative is the DECREASE in her altitude that will come about from her traveling downhill. From her original altitude to the altitude she is when she has traveled 7 km downhill, she will be at an altitude of (s - 63) m, if her original altitude was say, "s" m. This altitude would definitely be a positive number, not a negative one.
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