Practicing Success
A and B started their journeys from X to Y and Y to X, respectively. After crossing each other, A and B completed their remaining journey in 6\(\frac{1}{8}\) and 8 h respectively. If speed of A is 32 km/h, find the speed of B (km/h). |
28 21 25 34 |
28 |
Let meeting time = t hours, speed of A = S1 and speed of B = S2 time taken by A after meeting = t1 time taken by B after meeting = t2, ATQ, t1 = 6\(\frac{1}{8}\) = \(\frac{49}{8}\) t2 = 8 \(\frac{S_1}{S_2}\) = \(\sqrt {\frac{t_2}{t_1}}\) \(\frac{32}{S_2}\) = \(\sqrt {\frac{\frac{49}{8}}{8}}\) \(\frac{32}{S_2}\) = \(\sqrt {\frac{64}{49}}\) \(\frac{32}{S_2}\) = \(\frac{8}{7}\) S2 = 7 × 4 = 28
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