A) 1
B) 2
C) 3
D) 5
Correct Answer: C
$ \therefore $ When A covers the distance of $ 5\times 400=2000m $ Then B will cover the distance of $ 4\times 400=1600 $ That is A will meet B once in covering 1600 m.
$ \therefore $ A will meet B 3 times in covering 4800 m. Thus, A will pass B 3 times in 5 km race.