An assembler uses seven key components in its final product. These components are purchased

from different suppliers. Historical data shows that the reliabilities of the purchased components

are as follows:

Component Reliability

$10\mathrm{.}990$

$20\mathrm{.}990$

$30\mathrm{.}980$

$40\mathrm{.}995$

$50\mathrm{.}965$

$60\mathrm{.}985$

$70\mathrm{.}995$

The assembler purchases $2000$ units and inspects the products after production. The total direct

cost of final products is $$500$ per unit. After inspection, $30\%$ of the defective items can be fixed

and on average the rework cost is $$50$ per unit. Calculate the actual unit cost considering the

reliability.