A person walking at 4 Kmph reaches his office 8 minutes late. If he walks at 6 Kmph, he reaches there 8 minutes earlier. How far is the office from his house?

S1×S2/S2-S1 × T1+T2/60 = 4×6/2 × 16/6 = 24/2 × 16/60 = 8 × 2/5 = 16/5 = 3 1/5 Km