posted by Katherine on .
still don't get it.....Our class planned a holiday party for disadvantaged kids.Some of us baked cookies for the party.On the day of the party,we found we could divide the cookies into packets of two, three, four, five, or six and have just one cookie left over in each case.If we divided them into packets of seven, there would be no cookies left over. What is the least number of cookies the class could have baked?__________
Since divided into bags of 2,3,4,5,6, all left one cookie, we have also another way.
Find the LCM (lowest common multiple) of 2,3,4,5,6. Call this L.
Check if L+1 is divisible by 7. If it is, L is your answer. If it is not, try 2L+1, 3L+1, ... until it is divisible by 7. You will not have to try more than 7 times.
If you are not sure how to find the LCM of 2,3,4,5,6, post again.