Fred,Ned,and Ted Must Make Some Party Hats by Folding Up

Multiple Choice

Fred,Ned,and Ted must make some party hats by folding up pieces of paper.When working alone,they could make ten hats an hour each.If the Ringelmann effect occurs,when Fred works with Ned they will turn out ___ hats an hour each,and when Ted joins them,they will turn out ___ hats an hour each.

A) 12;14
B) 5;1
C) 8;6
D) 4;3
E) 15;20