I need help in accounts

Specialization—the division of labor—enhances productivity and efficiency by a) allowing workers to take advantage of existing differences in their abilities and skills. b) avoiding the time loss involved in shifting from one production task to another. c) allowing workers to develop skills by working on one, or a limited number, of tasks. d)all of the means identified in the other answers.

Consider the following information on stocks a, b, c and their returns (in decimals) in each state: state prob. of state a b c boom 20% 0.27 0.22 0.16 good 45% 0.16 0.09 0.07 poor 25% 0.03 0 0.03 bust 10% -0.08 -0.04 -0.02 if your portfolio is invested 25% in a, 40% in b, and 35% in c, what is the standard deviation of the portfolio in percent? answer to two decimals, carry intermediate calcs. to at least four decimals.

Aproduction line has three machines a, b, and c, with reliabilities of .96, .86, and .85, respectively. the machines are arranged so that if one breaks down, the others must shut down. engineers are weighing two alternative designs for increasing the line’s reliability. plan 1 involves adding an identical backup line, and plan 2 involves providing a backup for each machine. in either case, three machines (a, b, and c) would be used with reliabilities equal to the original three. a. compute overall system reliability under plan 1. (round your intermediate calculations and final answer to 4 decimal places.) reliability b. compute overall system reliability under plan 2. (round your intermediate calculations and final answer to 4 decimal places.) reliability c. which plan will provide the higher reliability? plan2plan1