SOLUTION: Aki’s Bicycle designs has determined that when x hundred bicycles are built, the average cost per bicycle is given by C(x)=0.5x^2-0.9x+1.861, where C(x) is in hundreds of dollars.

Algebra ->  Average -> SOLUTION: Aki’s Bicycle designs has determined that when x hundred bicycles are built, the average cost per bicycle is given by C(x)=0.5x^2-0.9x+1.861, where C(x) is in hundreds of dollars.       Log On


   



Question 1098325: Aki’s Bicycle designs has determined that when x hundred bicycles are built, the average cost per bicycle is given by C(x)=0.5x^2-0.9x+1.861, where C(x) is in hundreds of dollars. How many bicycles should the shop build to minimize the average cost per bicycle?
Found 2 solutions by ikleyn, josmiceli:
Answer by ikleyn(52809) About Me  (Show Source):
You can put this solution on YOUR website!
.
The minimal average cost per bicycle is achieved at 

    x = {{-(-0.9)/(2*0.5)}}} = 0.9, 

which corresponds to 90 bicycles.


Answer.  90 bicycles should be built  per day to minimize the average cost per bicycle.


When you have a quadratic function   y = ax^2 + bx + c   with  a > 0,

it achieves its minimum at   x = -b%2F%282a%29.


See the lessons
    - HOW TO complete the square to find the minimum/maximum of a quadratic function
    - Briefly on finding the minimum/maximum of a quadratic function
    - HOW TO complete the square to find the vertex of a parabola
    - Briefly on finding the vertex of a parabola
in this site.


Also,  you have this free of charge online textbook in ALGEBRA-I in this site
    - ALGEBRA-I - YOUR ONLINE TEXTBOOK.

The referred lessons are the part of this textbook under the topic "Finding minimum/maximum of quadratic functions".


Save the link to this online textbook together with its description

Free of charge online textbook in ALGEBRA-I
https://www.algebra.com/algebra/homework/quadratic/lessons/ALGEBRA-I-YOUR-ONLINE-TEXTBOOK.lesson

to your archive and use it when it is needed.



Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
+C%28x%29+=+.5x%5E2+-+.9x+%2B+1.861+
--------------------------------
The formula for the x-value of the
minimum,is:
+x%5Bmin%5D+=+-b%2F%282a%29+ where
+a+=+.5+
+b+=+-.9+
-------------
+x%5Bmin%5D+=+%28-%28-.9%29%29+%2F+%28+2%2A.5+%29+
+x%5Bmin%5D+=+.9%2F1+
+x%5Bmin%5D+=+.9+
+.9%2A100+=+90+
The shop should build 90 bikes to minimize cost
-------------------------
check:
Here's the plot:
+graph%28+400%2C+400%2C+-2%2C+7%2C+-3%2C+15%2C+.5x%5E2+-+.9x+%2B+1.861+%29+
Looks about right, +x%5Bmin%5D+=+.9+