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A, B and C start at the same time in the same direction to run around a circular stadium. A completes a round in 252 sec, B in 308 sec and C in 198 sec, all starting from the same point. After what time will they again meet at the stating point again ?
Answer & Solution
Correct Answer:
Option
A
Time taken by A
= 252 sec
= 22 ×32 ×7
Time taken by B
= 308 sec
= 22 × 7 × 11
Time taken by C
= 198 sec
= 2 × 9 × 11
Together will meet at starting point :
= L.C.M. (252, 308, 198)
= 22 × 32 × 7 × 11 sec
So, required time (minutes)
$$\eqalign{ & {\text{ = }}\frac{{4 \times 9 \times 7 \times 11}}{{60}} \cr & = 46\min 12\sec \cr} $$
= 252 sec
= 22 ×32 ×7
Time taken by B
= 308 sec
= 22 × 7 × 11
Time taken by C
= 198 sec
= 2 × 9 × 11
Together will meet at starting point :
= L.C.M. (252, 308, 198)
= 22 × 32 × 7 × 11 sec
So, required time (minutes)
$$\eqalign{ & {\text{ = }}\frac{{4 \times 9 \times 7 \times 11}}{{60}} \cr & = 46\min 12\sec \cr} $$
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