Circular track: number of distinct meeting points from the speed ratio

This type of question, asked 3 times: 14 Jul 2023 S3, 19 Jul 2023 S2, 19 Jul 2023 S3. All 3 questions below, oldest first.

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Question 1
14 Jul 2023 S3
60 $Two friends P and Q simultaneously start running from same point around a circular track. They run in the same direction. P runs at 6 m/sec and Q runs at b m/sec. If they cross each other at exactly two points on the circular track and b is a natural number less than 6, then how many values can b take?$
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Question 2
19 Jul 2023 S2
53 $Two persons started running on a circular track simultaneously with speeds of 20 m/s and 30 m/s in opposite directions. If the circumference of the circular track is 100 m, then find at how many distinct points they will cross each other?$
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Question 3
19 Jul 2023 S3
60 $Two persons started running on a circular track at a speed of 20 m/s and 30 m/s in opposite directions. If the circumference of the circular track is 100 m, find at how many distinct points they will cross each other?$
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Question 1