



 
Eileen, The number of shells is a multiple of 8 minus 5 so belongs to the set of numbers: 3, 11, 19, 27, ... (this really is the same as saying it is a multiple of 8 plus 3). The number of shells is a multiple of 7 plus 3 so belongs to the set of numbers: 10, 17, 24. .. . (note from the context we have to start at 10, not 3, this time). Write out these sequences a little farther and you'll see where they meet. Penny
8 shells per girl would need 5 more shells, and 7 shells per girl would need 3 fewer. So how many shells difference does one more shell per girl make? Good Hunting!
 


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