A ship sails out to a mark at the speed of 15 km/h and sails back to the starting point at the speed of 10 km/h. The average speed of sailing of the ship is:
Answer & explanation
Correct answer: option 1
Average Speed = \(\frac{2× S1 × S2 }{S1 + S2}\)
= \(\frac{2× 15 × 10 }{15 + 10}\)
= \(\frac{300 }{25}\)
= 12 km/h