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A person in a car drives along a straight road from point A to point B at a speed of 60 km/hour for 15 minutes and then from point B to point C at a speed of 90 km/hour for 10 minutes. The average speed of his travel from point A to C is1. 75 km/hr2. 72 km/hr3. 68 km/hr4. 78 km/hr |
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Answer» Correct Answer - Option 2 : 72 km/hr Formula used: Average speed = Total distance/Total time Distance = Speed × Time Calculation: Distance from A to B = 60 × (15/60) = 15 km Distance from B to C = 90 × (10/60) = 15 km Average speed = (15 + 15)/(15/60 + 10/60) = 72 km/hr ∴ The average speed of his travel from point A to C is 72 km/hr |
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