A manufacturer determines that the number of drills it can sell is given by the formula D=-3p^2+180p-280, where p is the price of the drills in dollars.

Question

anonymous · Answer

a.  At what price will the manufacturer sell the maximum number of drills? 
b.  What is the maximum number of drills that can be sold?

anonymous · Answer

Max point happens at x = -b/2a

anonymous · Answer

Here x is p!

anonymous · Answer

Understood but i am still confused....

anonymous · Answer

on this question.... i keep trying to get a. but it always turns out to be 84. here are the answer choices $30; 2,420 drills
$90; 8,380 drills
$60; 280 drills
$32; 2,427 drills

anonymous · Answer

What do you get with p = 180/ 6 = ...?

anonymous · Answer

30

anonymous · Answer

u can use differentiation to obtain the results
on differentiating  u have 
-6p+180=0
or p=30
at this value of p the above expression may be maximum or minimum
to check u differentiate (the result once more)
now it stands -6
thus at p=30 the second ordr differentiation is 
neagtive 
and hence at p=30, D is amximum
in order to obtain the max value of D use p=30 in D
hope rest u get it...

anonymous · Answer

Okay i got $30; 2,420 drills
Is this correct for both questions?

anonymous · Answer

Does it take you 16hrs to plug 30 into the equation ?

anonymous · Answer

no, im sorry i fell asleep.