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

\( \frac{10 + 8 + 10 + 8}{4} \) = \( \frac{36}{4} \) = 9

There are 2 4-passenger taxis available so that's 2 x 4 = 8 total seats. There are 10 people needing transportation leaving 10 - 8 = 2 who will have to find other transportation.

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

\( \frac{4}{5} \) ÷ \( \frac{2}{5} \) = \( \frac{4}{5} \) x \( \frac{5}{2} \)

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

\( \frac{4}{5} \) x \( \frac{5}{2} \) = \( \frac{4 x 5}{5 x 2} \) = \( \frac{20}{10} \) = 2

Christine scored 87% on the test meaning she earned 87% of the possible points on the test. There were 280 possible points on the test so she earned 280 x 0.87 = 244 points. Each question is worth 4 points so she got \( \frac{244}{4} \) = 61 questions right.

To subtract these fractions, first find the lowest common multiple of their denominators. The first few multiples of 3 are [3, 6, 9, 12, 15, 18, 21, 24, 27, 30] and the first few multiples of 9 are [9, 18, 27, 36, 45, 54, 63, 72, 81, 90]. The first few multiples they share are [9, 18, 27, 36, 45] making 9 the smallest multiple 3 and 9 share.

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

\( \frac{4 x 3}{3 x 3} \) - \( \frac{4 x 1}{9 x 1} \)

\( \frac{12}{9} \) - \( \frac{4}{9} \)

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

\( \frac{12 - 4}{9} \) = \( \frac{8}{9} \) = \(\frac{8}{9}\)