MAT Exam 2021 Paper

Concept:All three meet again at the starting point when the time taken is a common multiple of their individual lap times. So, find the LCM of their lap times.Explanation:Length of circular track $= 120 \ \mathrm{m}$. Time taken by $A$ to complete one lap $= \frac{120}{5} = 24 \ \mathrm{s}$. Time taken by $B$ to complete one lap $= \frac{120}{8} = 15 \ \mathrm{s}$. Time taken by $C$ to complete one lap $= \frac{120}{10} = 12 \ \mathrm{s}$. The required time is the LCM of $24$, $15$, and $12$. LCM of $24, 15, 12 = 120 \ \mathrm{s}$. Converting to minutes: $120 \ \mathrm{s} = 2 \ \mathrm{min}$.Answer:After $2$ minutes. Therefore, the correct option is B.