Multiple choice

A and B walk round a circular track They start at 8 am from the same point in opposite directions A and B walk at a speed of 2 rounds per hour and 3 rounds per hour respectively How many times shall they cross each other before 9.30 am

  1. 5

  2. 6

  3. 7

  4. 8
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Relative speed = 2 + 3 = 5 rounds per hour. Time interval = 1.5 hours. Total relative distance = 5 * 1.5 = 7.5 rounds. They cross each other 7 times.

AI explanation

When two objects move in opposite directions on a circular track, their relative speed in rounds per hour is the sum of their individual speeds: 2 plus 3 equals 5 rounds per hour. The total time elapsed from 8 am to 9:30 am is 1.5 hours. The total number of times they cross each other is the relative speed multiplied by the time, so 5 times 1.5 equals 7.5, which means they cross 7 full times before 9:30 am. The result is 7.

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