7) batteries properties battery brand average life cost a 12 hours $0.50 b 18 hours $2.00 c 24 hours $3.50 if a battery is needed for a smoke detector where the biggest priority is for the device to last as long as possible, then which brand is the best choice? a) battery a b) battery b c) battery c d) all 3 brands are equally good choices.

Without caring the cost of battery then battery C last the longest for average of 24 hrs. but if we include the cost, then we should calculate the cost per hour.

A.    $ 0.5 / 12 hrs = $ 0.042 per hr

B.    $ 2 / 18 hrs = $ 0.11 per hr

C.    $3.50 / 24 hrs = $ 0.15 per hrs

So the cheapest is battery A

with the invention of the automobile, the woman of the house could drive to the store and get groceries. women were also free to socialize more. during world war ii women were allowed to work in factories to the war effort and could drive to work or ride mass transit buses to their jobs.