The speed of a boat along the current and against the current are
| The speed of a boat along the current and against the current are 10 km/hr and 8 km/hr respectively. What is the speed of boat (in km/hr) in still water?
A. 2
B. 9
C. 4.5
D. 6
Please scroll down to see the correct answer and solution guide.
Right Answer is: B
SOLUTION
Let the speed of the boat is x and speed of the current is y.
Speed of a boat along the current (x + y) = 10 km/hr ----Equation(i)
Speed of a boat against the current (x - y) = 8 km/hr ---- Equation(ii)
Added the equation(i) and equation(ii)
⇒ x + y + x - y = 18
⇒ 2x = 18
⇒ x = 18/2 = 9km/hr
Speed of the boat is 9 km/hr