## Monday, July 20, 2009

### Field Trip Permission Form

Mt Ida day summer camp is having a field trip next week. In order to go on a trip each out of 400 campers should bring a field trip permission form home and return it back with a parents' signature. From the past camp experience, only about 90% of the forms sent are reaching parents, getting signed and returned back on the next day. The rest of the forms are disappearing somewhere in the backpacks alongside wet swim suits, gimp and snack crumbs. The question is, when should camp management start sending home the permission slips, so that in a week they would have all the forms back.
Note: floating point numbers could be rounded.

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Alin Grin said...
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Alin Grin said...

End of first week: 90% of 400 = 360
End of second week: 90% of 40 = 36
End of third week: 90% of 4 = 3.6
90% of 0.4 = 0.26

Therefor starting 3 weeks before the trip should be sufficient.

Maria said...

You are right!
Only it is 3 days rather than 3 weeks.
After the first day, 360 campers return the signed form and 40 loose it.
After the second day, from these 40 campers, 36 return the signed form and 4 misplace it again.
After the third day, out of 4 remaining campers, 3.6 return the form back and 0.4 forget again.

The note about rounding was a hint that we could just approximate 3.6 as 4 and 0.4 as 0.
So, after 3 attempts, all 400 campers are expected to have permission slip signed and ready for a field trip.

By the way, this was inspired by my own "never got this permission form" experience. After 3 camp phone calls, an improvised permission form and a real form, my son was finally able to take a field trip today. Unless it got canceled due to rain.