"Robert can swim the first 50 meters of a race in 1 minute. Then he slows down by 12 seconds for each of the next 50 meters of a race. How long will it take Robert to swim a 400-meter race?

440

To answer this question, we will calculate the time it takes Robert to swim each segment of the race and then sum these times to find the total time for the entire 400-meter race.

Let's break down the race into segments:

Segment 1: First 50 meters
Robert can swim the first 50 meters in 1 minute.

Segment 2: Next 50 meters
After the first 50 meters, Robert slows down by 12 seconds for each additional 50 meters. Since the race is 400 meters long, there are 7 additional 50-meter segments after the first one. So, Robert will take 12 seconds longer for each of these segments.
Therefore, for the next 50 meters, he will take 1 minute + 12 seconds = 1 minute and 12 seconds.
For the subsequent 50-meter segments, he will keep adding another 12 seconds. So, the times for the remaining segments are as follows:
- Segment 3: 1 minute + 2 × 12 seconds = 1 minute and 24 seconds
- Segment 4: 1 minute + 3 × 12 seconds = 1 minute and 36 seconds
- Segment 5: 1 minute + 4 × 12 seconds = 1 minute and 48 seconds
- Segment 6: 1 minute + 5 × 12 seconds = 2 minutes
- Segment 7: 1 minute + 6 × 12 seconds = 2 minutes and 12 seconds
- Segment 8: 1 minute + 7 × 12 seconds = 2 minutes and 24 seconds

Now, let's find the total time for the entire race by adding up the times for each segment:
Total time = Segment 1 time + Segment 2 time + Segment 3 time + ... + Segment 8 time

Total time = 1 minute + 1 minute and 12 seconds + 1 minute and 24 seconds + 1 minute and 36 seconds + 1 minute and 48 seconds + 2 minutes + 2 minutes and 12 seconds + 2 minutes and 24 seconds

When you add up these times, you will find that the total time for Robert to swim a 400-meter race is 12 minutes and 24 seconds.