To add these distances, they must share the same unit so first you need to first convert the swim distance from meters (m) to kilometers (km) before adding it to the bike and run distances which are already in km. To convert 400 meters to kilometers, divide the distance by 1000 to get 0.4km then add the remaining distances:

total distance = swim + bike + run
total distance = 0.4km + 40.5km + 11.600000000000001km
total distance = 52.5km

By buying two shirts, Bob will save $18 x \( \frac{5}{100} \) = \( \frac{$18 x 5}{100} \) = \( \frac{$90}{100} \) = $0.90 on the second shirt.

The number of students taking German or Spanish is 5 + 11 = 16. Of that group of 16, 2 are taking both languages so they've been counted twice (once in the German group and once in the Spanish group). Subtracting them out leaves 16 - 2 = 14 who are taking at least one language. 29 - 14 = 15 students who are not taking either language.

To add these fractions, first find the lowest common multiple of their denominators. The first few multiples of 5 are [5, 10, 15, 20, 25, 30, 35, 40, 45, 50] and the first few multiples of 7 are [7, 14, 21, 28, 35, 42, 49, 56, 63, 70]. The first few multiples they share are [35, 70] making 35 the smallest multiple 5 and 7 share.

Next, convert the fractions so each denominator equals the lowest common multiple:

\( \frac{6 x 7}{5 x 7} \) + \( \frac{6 x 5}{7 x 5} \)

\( \frac{42}{35} \) + \( \frac{30}{35} \)

Now, because the fractions share a common denominator, you can add them:

\( \frac{42 + 30}{35} \) = \( \frac{72}{35} \) = 2\(\frac{2}{35}\)

By buying two shirts, Ezra will save $44 x \( \frac{25}{100} \) = \( \frac{$44 x 25}{100} \) = \( \frac{$1100}{100} \) = $11.00 on the second shirt.

So, his total cost will be
$44.00 + ($44.00 - $11.00)
$44.00 + $33.00
$77.00