Two motorists Anil and Sunil are practicing with two different sports cars: Ferrari and Maclarun, on the circular racing track, for the car racing tournament to be held next month. Both Anil and Sunil start from the same point on the circular track .Anil completes one round of the track in 1 minute and Sunil takes 2 minutes to compete a round. While Anil maintains same speed for all the rounds, Sunil halves his speed after the completion of each round. How many times Anil and Sunil will meet between the 6th round and 9th round of Sunil (6th and 9th round is excluded)? Assume that the speed of Sunil remains steady throughout each round and changes only after the completion of that round.
Explanation:
Anil and Sunil meet every time Anil gains a round over Sunil.
When Sunil completes one round of the track of length, say d, in 2 minutes, Anil meets Sunil every dd-d2 = 2 minutes
∴ Anil meets Sunil 2/2 = 1 time in his first round.
When Sunil completes one round of the track of length, say d, in 2n minutes, Anil meets Sunil every dd-d2n = 2n2n-1 minutes
∴ Anil meets Sunil 2n2n2n-1 = 2n - 1 times in his nth round.
∴Anil meets Sunil 27 – 1 = 127 times in the 7th round and 28 – 1 = 255 times in the 8th round.
∴ They will meet 127 + 255 = 382 times between the 6th and 9th rounds.
Hence, option (c).
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