A and B start running in opposite directions from the same point along...
Analysis
Let's analyze the problem step by step:
- A and B start running in opposite directions and meet at Q for the first time and at P (which is 120 m away from Q) for the second time.
- B and C start running in opposite directions and meet at Q for the first time and at P (which is 150 m away from Q) for the second time.
We need to find the number of distinct points at which A and C meet when they run on the same track in opposite directions.
Solution
To solve this problem, let's consider the time taken by each person to run from Q to P.
- From the given information, we know that B takes the same time to run from Q to P in both scenarios. Therefore, B's speed is constant.
- Let's assume the time taken by B to run from Q to P is t. Since the distance from Q to P is 120 m in the case of A and B, and 150 m in the case of B and C, we can set up the following equations:
Distance = Speed × Time
120 = Speed of A × t ...(1)
150 = Speed of C × t ...(2)
From equations (1) and (2), we can see that the ratio of the speeds of A and C is 120:150, which simplifies to 4:5.
Therefore, the speeds of A, B, and C can be represented as 4x, 5x, and 5y, respectively, where x and y are positive integers.
Since A and C are running in opposite directions, the relative speed between them is the sum of their speeds, which is (4x + 5y).
Finding the Number of Distinct Points of Intersection
To find the number of distinct points at which A and C meet, we need to find the number of times their relative speed becomes equal to the circumference of the circular track.
The relative speed of A and C is (4x + 5y). Let's find the values of x and y for which (4x + 5y) is a factor of 600.
- Factors of 600:
- 1, 2, 3, 4, 5, 6, 8, 10, 12, 15, 20, 24, 25, 30, 40, 50, 60, 75, 100, 120, 150, 200, 300, 600
- We can see that (4x + 5y) is a factor of 600 for the following values of x and y:
- x = 25, y = 0 (gives 100)
- x = 20, y = 12 (gives 160)
- x = 15, y = 24 (gives 180)
- x = 10, y = 36 (gives 200)
- x = 5, y = 48 (gives 220)
- x = 0, y = 60 (gives 240)
Therefore, A and C will meet at 6 distinct points on the circular track, excluding the starting point. However, since A