• # question_answer A, B and C starts at the same time in the same direction to run around a circular stadium. A completes a round in 252 s, B in 308 s and C in 198 s, all starting at the same point after what time will they next meet at the starting point again? A)  46 min 12 s B)  45 min C)  42 min 36 s D)  26 min 18 s

Required time = LCM OF 252, 308 AND 198 s Now, $252=2\,\times 2\times 3\times 3\times 7$ $308=2\times 2\times 7\times 11$ $198=2\times 3\times 3\times 11$ $\therefore$ $LCM=2\times 2\times 3\times 3\times 7\times 11$ $=36\times 77\,s$ $=\frac{36\times 77}{60}\,\min$ $=\frac{231}{5}=\,46\,\min \,12\,s$