# Thread: funny example the teacher gave us. dont know how to solve it.

1. ## funny example the teacher gave us. dont know how to solve it.

if i have 10 girlfriends and i see a different one each day (i see one and only one per day) and every week i wanted to see seven of them in a different order than the week before. how long could i continue until i have exhausted all possible combinations?

i said until they all find out about each other. i give it 2-3 months max. apparently that's not the right answer. so how do you solve this?

2. Originally Posted by bm203
if i have 10 girlfriends and i see a different one each day (i see one and only one per day) and every week i wanted to see seven of them in a different order than the week before. how long could i continue until i have exhausted all possible combinations?

i said until they all find out about each other. i give it 2-3 months max. apparently that's not the right answer. so how do you solve this?
Count the number of permutations of 7 from 10 objects, that is the number of weeks you can continue before a repeat.

CB