Correct Answer - Option 3 : 8 hrs

**Given:**

D = 700 km

A starts 3 hrs before B

A's speed = 55 km/h

B's speed = 52 km/h

**Concept:**

Relative speed in opposite direction is the sum of individual speeds.

**Formula used:**

Speed = distance/time

**Calculation:**

A's distance in 3 hrs = 55 × 3 = 165 km

Remaining distance = 700 - 165 = 535 km

Relative speed = 55 + 52 = 107 km/h

Time = 535/107 = 5 hrs

Required time = 3 + 5 = 8 hrs

**∴ The time taken is 8 hrs**