Apiston-cylinder device contains 6.95 kg of refrigerant-134a at 0.6 mpa and 70°c. the refrigerant is now cooled at constant pressure until it exists as a liquid at 22°c. if the surroundings are at 100 kpa and 25°c, determine (a) the exergy of the refrigerant at the initial and the final states and (b) the exergy destroyed during this process.

x = 50

Explanation:

Given that,

The total cost of production of spare parts of computer is given as

C=4000x-100x²+x³

Where x is the number of units of spare parts produced

We need to find the number of units of spare parts so that the average cost will be maximum.

Average cost,

For maximum average cost, put d(c)/dx = 0

So, the number of units of spare parts is 50.