Correct Answer - Option 2 : 2

**Given:**

Speed of boat in still water = 13 km/h

Distance = 3 km

Time taken = 12 minutes

**Formulas Used:**

Speed = Distance/Time

S_{(downstream)} = S_{(boat)} + S_{(stream)}

**Calculation:**

Speed = Distance/Time

⇒ S_{(downstream)} = (3 x 60)/12

⇒ S_{(downstream)} = 15 km/h

S_{(downstream)} = S_{(boat)} + S_{(stream)}

⇒ S_{(stream)} = S_{(downstream)} – S_{(boat)}

⇒ S_{(stream)} = 15 – 13

⇒ S_{(stream)} = 2 km/h

**∴** **The speed of stream is 2 km/h**

Conversion of Time from minutes to hours

1 min = (1/60) hour