The problem states that the world’s largest pool is 13 meters longer than the total length of 20 Olympic pools. We know that an Olympic pool is 50 meters long.

Let’s break it down:

1. The total length of 20 Olympic pools is: $20 \times 50 = 1000 \text{ meters}$

2. The world’s largest pool is 13 meters longer than this, so its length is: $1000 + 13 = 1013 \text{ meters}$

Thus, the world’s largest pool is 1013 meters long.

Would you like further details on this? Here are some related questions:

1. If the Olympic pool length was 55 meters, how long would the world’s largest pool be?
2. How long is 15 Olympic pools in total?
3. What would the world’s largest pool length be if it were 20 meters longer than the total length of 25 Olympic pools?
4. What if the world’s largest pool was 50 meters shorter than 20 Olympic pools; what would be its length?
5. If the world’s largest pool were 13 meters shorter than 20 Olympic pools, how long would it be?

Tip: To solve problems like this efficiently, always start by calculating the known total first, then adjust based on the conditions provided.