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

\( \frac{4}{8} \) x \( \frac{2}{7} \) = \( \frac{4 x 2}{8 x 7} \) = \( \frac{8}{56} \) = \(\frac{1}{7}\)

Average speed in miles per hour is the number of miles traveled divided by the number of hours:

Solving for time:

time = \( \frac{\text{distance}}{\text{speed}} \)
time = \( \frac{35mi}{35mph} \)
1 hour

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

\( \frac{9 + 7 + 11 + 5}{4} \) = \( \frac{32}{4} \) = 8

Average speed in miles per hour is the number of miles traveled divided by the number of hours:

To subtract these fractions, first find the lowest common multiple of their denominators. The first few multiples of 8 are [8, 16, 24, 32, 40, 48, 56, 64, 72, 80] and the first few multiples of 10 are [10, 20, 30, 40, 50, 60, 70, 80, 90]. The first few multiples they share are [40, 80] making 40 the smallest multiple 8 and 10 share.

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

\( \frac{8 x 5}{8 x 5} \) - \( \frac{2 x 4}{10 x 4} \)

\( \frac{40}{40} \) - \( \frac{8}{40} \)

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

\( \frac{40 - 8}{40} \) = \( \frac{32}{40} \) = \(\frac{4}{5}\)