To solve this problem using the ratio-proportion method, we need to focus on two aspects:

1. Walking speed: If the person walks twice as fast, they will cover the same distance in half the time each day.
2. Resting time: If the person rests twice as long, they will spend less time walking each day.

Let’s break this into steps:

Step 1: Analyze the original scenario

• The person covers the distance in 50 days.
• Each day consists of 24 hours.
• They rest 9 hours each day, leaving 15 hours for walking.

Step 2: New scenario after changes

In the new situation:

• The person now rests twice as long, meaning they rest for 2 × 9 = 18 hours a day.
• This leaves them only 24 - 18 = 6 hours for walking per day.
• However, they walk twice as fast, meaning they cover double the distance in those 6 hours compared to the original 15 hours of walking.

Step 3: Setting up the proportion

To maintain proportionality between the distance covered in both scenarios, let’s compare the original walking efficiency (distance covered per day) with the new one:

• Originally, the person walked for 15 hours at normal speed.
• In the new scenario, they walk for 6 hours at twice the speed, so their effective walking time is equivalent to 6 × 2 = 12 hours at normal speed.

Now, let’s set up the ratio of days:

• Originally, they walked 15 hours per day for 50 days.
• In the new scenario, their effective walking time is 12 hours per day.

Thus, the ratio of time required is proportional to the walking hours:

$\frac{50 \text{ days}}{x \text{ days}} = \frac{12 \text{ hours/day}}{15 \text{ hours/day}}$

Solving for $x$:

$x = 50 \times \frac{15}{12} = 50 \times \frac{5}{4} = 62.5 \text{ days}.$

Step 4: Adjust for the doubled resting time

Since they now have less walking time and need to maintain the same total distance covered, it will take them twice as long as before to finish, so:

$\text{Total time} = 62.5 \times 2 = 125 \text{ days}.$

Thus, it will take 125 days to cover the same distance.

Would you like more details or have any questions?

Here are five follow-up questions:

1. How would the scenario change if the resting time increased by 50% instead of doubling?
2. What would happen if the person walked at 1.5 times the original speed?
3. Can you derive a general formula for walking time based on changes in speed and rest time?
4. How would reducing the rest time by half affect the total days taken?
5. What if the person could rest for 8 hours and walked 1.5 times faster?

Tip: When using ratio-proportion, always ensure both sides of the ratio represent equivalent quantities (e.g., time vs. distance) to maintain balance in the equation.