Related Rates: demand eqn q(p) = 10 - 0.1p; if increased at 20/wk, find...

jtstien

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I am having trouble with the attached related rates hmwk problem.

2. Suppose the demand equation is given by: q (p) = 10 - 0.1p, where q represents the number of items manufactured (and sold) at a price p dollars. If the quantity demanded is increased at a rate of 20 per week, find the following:

(a) The rate of change of p with respect to time.

(b) The rate of change of revenue with respect to time when q = 4.
** Hint: Revenue equals price times quanity and you'll also need the answer you found in (a).


For part A, I got dp/dt=-200$.

q = items manufactured
p = price

dp/dt = ?

dq/dt = 20

q(p) = 10 - 0.1p

dq/dt = -0.1 dp/dt

20/-0.1 = (-0.1/-0.1) dp/dt

dp/dt = -200

I'm not even sure if that is correct. For part B I don't know where to begin. Any help would be greatly appreciated.
 

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I am having trouble with the attached related rates hmwk problem.

2. Suppose the demand equation is given by: q (p) = 10 - 0.1p, where q represents the number of items manufactured (and sold) at a price p dollars. If the quantity demanded is increased at a rate of 20 per week, find the following:

(a) The rate of change of p with respect to time.

(b) The rate of change of revenue with respect to time when q = 4.
** Hint: Revenue equals price times quanity and you'll also need the answer you found in (a).


For part A, I got dp/dt=-200$.

q = items manufactured
p = price

dp/dt = ?

dq/dt = 20

q(p) = 10 - 0.1p

dq/dt = -0.1 dp/dt

20/-0.1 = (-0.1/-0.1) dp/dt

dp/dt = -200

I'm not even sure if that is correct. For part B I don't know where to begin. Any help would be greatly appreciated.

Get the equation for revenue:

R(vevenue) = q * p

Now differentiate and continue.....
 
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