One of the formulas for inventory management says that the average weekly cost of ordering, paying for, and holding merchandise is
A(q) = km/q + cm + hq/2
, where q is the quantity ordered when things run low (shoes, TVs, brooms, or whatever the item might be); k is the cost of placing an order (the same, no matter how often you order); c is the cost of one item (a constant); m is the number of items sold each week (a constant); and h is the weekly holding cost per item (a constant that takes into account things such as space, utilities, insurance, and security).
Find dA/dq and d²A/dq².

Answer

3.5 hours

Step-by-step explanation:

Let us represent

The time spent walking as x

The time spent riding as y

Jim began a 146​-mile bicycle trip to build up stamina for a triathlete competition.​ Unfortunately, his bicycle chain​ broke, so he finished the trip walking. The whole trip took 5 hours.

Hence:

x + y = 5 Equation 1

x = 5 - y

If Jim walks at a rate of 4 miles per hour and rides at 40 miles per​ hour,

The formula for Distance = Speed × time. Hence,

4 × x + 40 × y = 146 miles

4x + 40y = 146 Equation 2

We substitute 5 - y for x in Equation 2

4(5 - y) + 40y = 146

20 - 4y + 40y = 146

Subtract 20 from both sides

20 - 20 - 4y + 40y = 146 - 20

- 4y + 40y = 146 - 20

36y = 126

y = 126/36

y = 3.5 hours

Since the time he spent raiding his bicycle is represented by "y", the amount of time he spent on the bicycle is 3.5 hours      

I think this is right I had this question I think it was the same one I dont know tho