A boat goes to a certain point at a speed of 15 km per hour and returns to the starting point at a speed of 10 km per hour. How much is the average speed of the boat in km per hour for the entire journey?
A
12.5
B
12
C
11.25
D
None of these
Correct Option:
B
Explanation
For equal distances, average speed = 2uv/(u + v) = (2 × 15 × 10)/(15 + 10) = 12 km/h. Therefore, option B is correct.
