The number of students taking German or Spanish is 9 + 13 = 22. Of that group of 22, 6 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 22 - 6 = 16 who are taking at least one language. 28 - 16 = 12 students who are not taking either language.

A number with an exponent (b^e) consists of a base (b) raised to a power (e). The exponent indicates the number of times that the base is multiplied by itself. A base with an exponent of 1 equals the base (b¹ = b) and a base with an exponent of 0 equals 1 ( (b⁰ = 1).

To divide fractions, invert the second fraction and then multiply:

\( \frac{3}{9} \) ÷ \( \frac{2}{8} \) = \( \frac{3}{9} \) x \( \frac{8}{2} \)

To multiply fractions, multiply the numerators together and then multiply the denominators together:

\( \frac{3}{9} \) x \( \frac{8}{2} \) = \( \frac{3 x 8}{9 x 2} \) = \( \frac{24}{18} \) = 1\(\frac{1}{3}\)

There are 3 3-passenger taxis available so that's 3 x 3 = 9 total seats. There are 11 people needing transportation leaving 11 - 9 = 2 who will have to find other transportation.

To find the average of these 4 numbers add them together then divide by 4:

\( \frac{16 + 10 + 14 + 12}{4} \) = \( \frac{52}{4} \) = 13