How many quarter pound burgers can george make out of 3 1/2 pounds of ground beef?

Assuming that there is no wastage of beef.

Note that 3 1/2 = 7/2 = 14/4 = 14 * 1/4

This means that we can have 14 sets of quarter pound beef.

This in turn means that George can make 14 quarter pound burgers.

If you take it down to the unit rate George would be able to make 4 quarter pound burgers for every pound (because a quarter is one fourth) you can display this as 4/1 multiply the top and bottom by 3 and get 12/3 meaning George can make 12 out of 3 pounds and the 1/2 pound would be equivalent to 2 fourths or in this case 2 more quarter pound burgers add it to the 12 and the final answer would be 14.