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Question

A person takes one hour more to cover a certain distance walking at a speed of 2 km/hour compared to walking at 3 km/hour. The distance is

The correct answer is

6 km

Let's figure out the distance the person traveled using the information about their speeds and the difference in time taken.

Distance, Speed, and Time

The relationship between distance, speed, and time is a fundamental concept in motion problems. It is given by the formula:

\( \text{Distance} = \text{Speed} \times \text{Time} \)

From this formula, we can also express time as:

\( \text{Time} = \frac{\text{Distance}}{\text{Speed}} \)

Setting Up the Problem Variables

Let the unknown distance be \(d\) kilometers.

We are given two different speeds at which the person walks:

  • Speed 1 (\(S_1\)) = 2 km/hour
  • Speed 2 (\(S_2\)) = 3 km/hour

Let \(T_1\) be the time taken to cover the distance \(d\) at Speed 1, and \(T_2\) be the time taken to cover the same distance \(d\) at Speed 2.

Calculating Time Taken at Each Speed

Using the formula \( \text{Time} = \frac{\text{Distance}}{\text{Speed}} \), we can write the time taken for each speed:

  • Time taken at 2 km/hour: \( T_1 = \frac{d}{2} \) hours
  • Time taken at 3 km/hour: \( T_2 = \frac{d}{3} \) hours

Using the Time Difference Information

The problem states that the person takes one hour more to cover the distance walking at 2 km/hour compared to walking at 3 km/hour. This means the difference between the two times is 1 hour.

So, we can write the equation:

\( T_1 - T_2 = 1 \)

Substitute the expressions for \(T_1\) and \(T_2\) we found earlier:

\( \frac{d}{2} - \frac{d}{3} = 1 \)

Solving for the Distance \(d\)

Now, we need to solve this equation to find the value of \(d\).

To subtract the fractions on the left side, we need a common denominator. The least common multiple of 2 and 3 is 6.

Multiply the first term by \( \frac{3}{3} \) and the second term by \( \frac{2}{2} \):

\( \frac{d}{2} \times \frac{3}{3} - \frac{d}{3} \times \frac{2}{2} = 1 \)

\( \frac{3d}{6} - \frac{2d}{6} = 1 \)

Combine the fractions on the left side:

\( \frac{3d - 2d}{6} = 1 \)

\( \frac{d}{6} = 1 \)

To isolate \(d\), multiply both sides of the equation by 6:

\( d = 1 \times 6 \)

\( d = 6 \)

Final Distance

The distance covered is 6 kilometers.

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Important Questions from Speed Time and Distance

  1. Daksh travels 200 km at 50 km/hr, the next 252 km at 42 km/hr and the next 204 km at 51 km/hr. What is his average speed (in km/hr) for the whole journey? (Round off your answer to two decimal places)
  2. A bus travelling at 66 km/hr completes a journey in 15 hours. What should be its speed to cover the same distance in 5 hours?
  3. Train A leaves station M at 8:00 a.m. and reaches station N at 3:00 p.m. on the same day. Train B leaves station N at 10:00 a.m. and reaches station M at 3:00 p.m. on the same day. Find the time when Trains A and B meet.
  4. A bus travelling at 95 km/hr completes a journey in 10 hours. What should be in its speed to cover the same distance in 5 hours?
  5. Rishi travels 198 km at 66 km/hr, the next 584 km at 73 km/hr and the next 656 km at 82 km/hr. What is his average speed (in km/hr) for the whole journey? (Round off your answer to two decimal places)

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