एका गाडीने ताशी 40 कि. मी. वेगाने पहिला अर्धा प्रवास पूर्ण केला व ताशी 60 कि.मी. वेगाने दुसरा अर्धा प्रवास पूर्ण केला तर त्या गाडीचा सरासरी वेग किती होता ?

The correct answer is Option A (48 km/h).

Key Points:
• Average Speed for Equal Distance Halves:
• Formula: When two equal parts of a journey are traveled at speeds x and y, the average speed is given by the Harmonic Mean:
• Average Speed = (2xy)/(x + y)
• Given:
• x = 40 km/h
• y = 60 km/h
• Average Speed = (2 × 40 × 60)/(40 + 60) = (4800)/(100) = 48 km/h
• Note: A common mistake is taking the arithmetic mean (40+60)/(2) = 50 km/h, which is incorrect because the travel times for both halves are unequal.
• Key Takeaway: Average speed for equal distances is (2xy)/(x+y) = (2 × 40 × 60)/(100) = 48 km/h.