By buying two shirts, Alex will save $15 x \( \frac{40}{100} \) = \( \frac{$15 x 40}{100} \) = \( \frac{$600}{100} \) = $6.00 on the second shirt.

The yearly interest charged on this loan is the annual interest rate multiplied by the amount borrowed:

interest = annual interest rate x loan amount

i = (\( \frac{6}{100} \)) x $500
i = 0.01 x $500
i = $5

To simplify this fraction, first find the greatest common factor between them. The factors of 20 are [1, 2, 4, 5, 10, 20] and the factors of 80 are [1, 2, 4, 5, 8, 10, 16, 20, 40, 80]. They share 6 factors [1, 2, 4, 5, 10, 20] making 20 their greatest common factor (GCF).

Next, divide both numerator and denominator by the GCF:

\( \frac{20}{80} \) = \( \frac{\frac{20}{20}}{\frac{80}{20}} \) = \( \frac{1}{4} \)

The distributive property for division helps in solving expressions like \({b + c \over a}\). It specifies that the result of dividing a fraction with multiple terms in the numerator and one term in the denominator can be obtained by dividing each term individually and then totaling the results: \({b + c \over a} = {b \over a} + {c \over a}\). For example, \({a^3 + 6a^2 \over a^2} = {a^3 \over a^2} + {6a^2 \over a^2} = a + 6\).

There are 4 3-passenger taxis available so that's 4 x 3 = 12 total seats. There are 14 people needing transportation leaving 14 - 12 = 2 who will have to find other transportation.