You are right. 5 is correct.
steps:
total: 13 ppl
republicans: 4
1st person: 13-4/13 9/13
2nd person: 12-4/12 (because one person was taken out). 8/12
Distance = rate x time
D = 450 mph x 2.5 h
D = 1,125 miles
The last set (choice D) is a subset of given set B.
The other 3 choices are wrong.
