A man, on tour travel first 160 km. at 64 km/hr. and the next 160 km. at 80 km/hr. The average speed for first 320 km. of the tour is?
Aptitude
Time and Distance
Choose an option
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A35.55 km/hr
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B71.11 km/hr
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C36 km/hr
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D72 km/hr
Answer
Correct Answer: 71.11 km/hr
Explanation
Average speed = 2uv / ( u + v ) km/hr =(2 x 64 x 80) / (64 + 80) km/hr = (2 x 64 x 80) / 144 km/hr. = 71.11 km/hr