The ratio of the distance between two places A and B to the distance between places B and C is 3 : 5 . A man travels from A to B at 30 km/h and from B - Quantitative Aptitude MCQ SSC Selection Post 2021 Matriculation Level 2026 | ExamTest.live

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The ratio of the distance between two places A and B to the distance between places B and C is 3 : 5 . A man travels from A to B at 30 km/h and from B to C at x km/h . If his average speed for the entire journey is 40 km/h, then what is the value of (x - 7) (in km/h)?

Solution & Step-by-step Explanation

Let the distance between A and B be 3 d and between B and C be 5 d .The total distance of the journey = 3 d + 5 d = 8 d .We can write the time taken for both components of the journey: t_{1} = \frac{Distance _{A B}}{Speed _{A B}} = \frac{3 d}{30} = \frac{d}{10} t_{2} = \frac{Distance _{BC}}{Speed _{BC}} = \frac{5 d}{x} The average speed is defined as the total distance divided by the total time: Average Speed = \frac{Total Distance}{t _{1} + t _{2}} 40 = \frac{8 d}{\frac{d}{10} + \frac{5 d}{x}} 40 = \frac{8}{\frac{1}{10} + \frac{5}{x}} \frac{1}{10} + \frac{5}{x} = \frac{8}{40} = \frac{1}{5} \frac{5}{x} = \frac{1}{5} - \frac{1}{10} = \frac{1}{10} x = 5 \times 10 = 50 km/h Now, compute the value of (x - 7) : x - 7 = 50 - 7 = 43 km/h

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The ratio of the distance between two places A and B to the distance between places B and C is 3 : 5 . A man travels from A to B at 30 km/h and from B to C at x km/h . If his average speed for the entire journey is 40 km/h, then what is the value of (x - 7) (in km/h)?

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