A girl scout troop uses 14 flashlight batteries on a three-night camping trip. If they are planning a seven-night trip, how many batteries should they bring?
There are several possible interpretations of this problem, resulting in different answers:
Suppose the flashlights are only used in the dark. Then the period for which they are used for the longer camping trip would be
But suppose the troop consists of
This requirement could be reduced by labelling the batteries and cycling them. For example, all
For the fourth and fifth nights, the scouts whose batteries had run out would receive fresh ones. On the last two nights the partially used batteries could be used instead. This scheme would use
Suppose the flashlights are only used during daylight (!), in order to practice signalling using morse code, with the scouts supposed to be sleeping at night. A three-night camping trip includes up to four periods of daylight, while a seven-night trip includes up to eight. So the battery requirement may be double for the longer trip, which would give us a figure of