let

b = the number of pairs of shoes that Bell has

g = the number of pairs of shoes that Gen has

j = the number of pairs of shoes that Jill has

Bell has more than two time as many pairs of shoes as Gen and more than twice as many as Jill:

b > 2g

b > 2j

both Gen and Jill have at lease 5 each

g >= 5

j >=5

follows

b > 2*5

b > 10

Bell has at least 10 pairs of shoes.