Select the correct answerTwo men, A and B, walk from P to Q, a distance of 21 km, at 3 and 4 km an hour respectively. B reaches Q, returns immediately and meets A at R. Find the distance from P to R?Options18 km19 km20 km22 km

To solve this problem, we need to understand that the time taken by both A and B to meet at point R is the same.

1. First, calculate the time taken by B to reach Q. The distance from P to Q is 21 km and B walks at a speed of 4 km/h. So, the time taken by B to reach Q is 21 km / 4 km/h = 5.25 hours.

2. In this time, A would have walked a certain distance towards Q. A walks at a speed of 3 km/h. So, in 5.25 hours, A would have walked 5.25 hours * 3 km/h = 15.75 km.

3. However, B has returned from Q and met A at R. This means that the distance from P to R is the distance that A has walked, which is 15.75 km.

4. But the options given are in whole numbers. So, we need to round 15.75 km to the nearest whole number, which is 16 km.

5. However, 16 km is not an option. This means that there might be a mistake in the problem or the options given. The closest option to 16 km is 18 km, but this is not the exact answer.

So, based on the information given in the problem, none of the options are correct.

To solve this problem, we need to understand that the time both men are walking is the same, even though they walk at different speeds.

1. First, we calculate the time it takes for B to walk to Q. The distance is 21 km and B walks at 4 km/h, so the time is 21 km / 4 km/h = 5.25 hours.

2. During this time, A is also walking. A walks at 3 km/h, so in 5.25 hours, A walks 3 km/h * 5.25 hours = 15.75 km.

3. Therefore, the distance from P to R, where A and B meet, is 15.75 km. However, this is not an option in the question.

4. The problem might be in the rounding of the numbers. If we don't round the time it takes for B to walk to Q, we get a more precise number: 21 km / 4 km/h = 5.25 hours.

5. If we multiply this time by A's speed, we get the distance A walks: 3 km/h * 5.25 hours = 15.75 km.

6. Rounding this number to the nearest whole number, we get 16 km. However, this is still not an option in the question.

7. The question might have a mistake. The correct answer should be 16 km, not any of the options given.

To solve this problem, we need to understand that the time both men are walking is the same, even though they walk at different speeds.

1. First, we calculate the time it takes for B to reach Q. The distance is 21 km and B walks at 4 km/h, so the time is Distance/Speed = 21 km / 4 km/h = 5.25 hours.

2. In this time, A will also have been walking. A walks at a speed of 3 km/h, so in 5.25 hours, A will have walked Speed * Time = 3 km/h * 5.25 h = 15.75 km.

3. Therefore, the distance from P to R, where A and B meet, is 15.75 km. However, this is not an option in the given answers.

4. The problem might be in rounding. If we round the time it takes for B to reach Q to 5 hours, then A would have walked Speed * Time = 3 km/h * 5 h = 15 km in this time.

5. But B would have walked for an additional 0.25 hours on his way back from Q to meet A. In this time, B would have covered Speed * Time = 4 km/h * 0.25 h = 1 km.

6. Adding this to the distance A walked gives the distance from P to R as 15 km + 1 km = 16 km.

7. However, this is still not an option in the given answers. It seems there might be a mistake in the problem or the answer options.