4.2 Vodacom has a cell phone plan that has a basic charge of R165 a month. The plan includes
400 free minutes and charges 10 cents for each additional minute of usage.
Write the monthly
costC
as a function of the number
x
of minutes used and graph
C
as a
function of
x
for
0<=x<=600
.
Question 5
Suppose that South African airways, states in its airline policy that all baggage must be box-
shaped with a sum of length, width, and height not exceeding 108 cm .
What are the dimensions and volume of a square-based box with the greatest volume under
these conditions? Explain your solution.