First, recall that
So if , then
.
Second,
We know that and
, which means we should also have
.
Third,
but as we've already shown, we need to have , so we pick the negative root.
Finally,
Unfortunately, none of the given answers match, so perhaps I've misunderstood one of the given conditions... In any case, this answer should tell you everything you need to know to find the right solution from the given options.
Answer:
2.25
Step-by-step explanation:
Given the cost model:
C(l) = l3 – l2 + l + 2.5
l = Length fo package
The length of a package that cost $11.00
11 = l³ - l² + l + 2.5
From the table given :
Length of mail which cost $11 will just be slightly greater Than 2 as the cost of 2 length mail cost 8.50
Taking l as 2.20
2.2^3 - 2.2^2 + 2.2 + 2.50 = 10.508
Taking a slightly higher value :
Put l = 2.25
2.25^3 - 2.25^2 + 2.25 + 2.50 = 11.078
Ww can conclude that the length of mail would be 2.25
