Correct Answer - Option 2 : 2 hours

**Given:**

Distance travelled by Bus = Distance travelled by Car = Distance travelled by Bike = 12 km

Ratio of speed by Bus, Car and Bike is 4 : 2 : 1

Total duration of journey = 7 hours

**Formula used:**

Speed = Distance/Time

**Calculations:**

Let the speed by Bus, Car and Bike be 4y, 2y, y respectively.

Total time = Time taken by Bus + Time taken by Car + Time taken by Bike

7 = (12/4y) + (12/2y) + (12/y)

⇒ 7 = (3/y) + (6/y) + (12/y)

⇒ 7 = 21/y

⇒ y = 21/7

⇒ y = 3

Time taken by car = 12/2y

⇒ 6/y

⇒ 6/3

⇒ 2 hours

**∴ The time taken by Car is 2 hours.**