Question

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.

Answer 1

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