The cost C of building a house is related to the number k of carpenters used and the number x of electricians used by the formula
C
=
15
,
000
+
50
k
2
+
60
x
2
.
(a) Assuming that 10 carpenters are currently being used, find the cost function C, marginal cost function C', and average function ¯
C
, all as a function of x.
C(x) = _____
C'(x) = _____
¯
C
(
x
)
=
_____
(b) Use te functions you obtained in part (a) to compute C'(16) and ¯
C
(16).
C'(16) = $ _____ per spot
¯
C
(16) = $ _____ per spot (Round your answer to two decimal places.)
Use these two answer to say whether the average cost is increasing or decreasing as the number of electricians increases.
a. The average cost is increasing as x increases.
b. The average cost is decreasing as x increases.
