Correct Answer - Option 4 : 46 km
Given:
The speed of the boat = 15 km/hr
Concept Used:
Upstream – If the boat is flowing in the opposite direction to the stream
Downstream – If the boat is flowing along the direction of the stream
Formula Used:
Speed = \( {Distance \ \over Time}\)
Upstream Speed = Speed of boat - the speed of the stream
Downstream Speed = Speed of boat + speed of the stream
Calculation:
Let the speed of the boat be x and stream be y
Up stream speed = x - y
Down stream speed = x + y
∴ (x + y) - (x - y) = 16
⇒ 2y = 16
⇒ y = 16/2 = 8 ----(1)
The speed of the boat in down stream = 15 + 8 = 23 km/hr
Distance covered = 23 × 2 = 46 km
∴ The distance covered in the downstream is 46 km
