Expert: Sherman D. - 8/29/2005

Question
1. the manager of a weeekend flea market knows from the past experience that if he charges x dollars for a rental space at the flea market, then the number y of spaces he can rent is given by the equation: y=200-4x what do the slope, y-intercept and the x-intercept of the graph represent?

2. jason leaves detroit at 2p.m. and drives at a constant speed west along I-96. he passes ann arbor 40mi from detroit, at 2:50p.m. a) express the dist. traveled in terms of the time elpased
b) what is the slope of this line? what does it represnt?

3) at the surface of the ocean, the water pressure is the same as the air pressure above the water, 15lb/in^2. below the surface the water pressure increases by 4.34lb/in^2 for every 10ft of descent.
a) express the water pressure as a function of the depth below the ocean surface?  

Answer
1.)
y = 200 - 4x
y = -4x + 200

slope = dollars/space
y-intercept = Max profit he will have before he rents out the spaces.
x-intercept = Max number of spaces he can rent out before he goes over his limit.

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2.)
If he traveled 40mi in 50 minutes, then thats S = 40/(5/6), S = 40 * (6/5), S = 240/5, S = 48 mph

s = d/t
d = st

a.)
d = (5/6)s

b.)
Slope = (5/6)
It represents the time elasped for every mile traveled.

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3.)
y = 4.34(x/10) + 15
y = (4.34/10)x + 15
y = (434/1000)x + 15
y = (217/500)x + 15
or
y = .434x + 15

since its every 10ft, 4.34 would become .434 every foot.

f(x) = .434x + 15

since it says to put it as a function.

I'm not 100% sure if all the problems are correct, since some word problems i have trouble doing. But i am almost certain that they are correct.