To subtract these radicals together their radicands must be the same:

4\( \sqrt{27} \) - 9\( \sqrt{3} \)
4\( \sqrt{9 \times 3} \) - 9\( \sqrt{3} \)
4\( \sqrt{3^2 \times 3} \) - 9\( \sqrt{3} \)
(4)(3)\( \sqrt{3} \) - 9\( \sqrt{3} \)
12\( \sqrt{3} \) - 9\( \sqrt{3} \)

Now that the radicands are identical, you can subtract them:

To take the square root of a fraction, break the fraction into two separate roots then calculate the square root of the numerator and denominator separately:

\( \sqrt{\frac{16}{9}} \)
\( \frac{\sqrt{16}}{\sqrt{9}} \)
\( \frac{\sqrt{4^2}}{\sqrt{3^2}} \)
\( \frac{4}{3} \)
1\(\frac{1}{3}\)

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 200 meters to kilometers, divide the distance by 1000 to get 0.2km then add the remaining distances:

total distance = swim + bike + run
total distance = 0.2km + 50.4km + 8.8km
total distance = 59.4km

The amount of flour you need is (3\(\frac{3}{8}\) - 1\(\frac{3}{8}\)) cups. Rewrite the quantities so they share a common denominator and subtract:

(\( \frac{27}{8} \) - \( \frac{11}{8} \)) cups
\( \frac{16}{8} \) cups
2 cups

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 = \( \frac{420mi}{60mph} \)
7 hours