9) Suppose it takes a plane 5 hours to travel from Philadelphia to San Francisco. It travels at an average speed of 500 miles per hour. What is the distance between
the two cities?

2500miles

Explanation:

Given parameters:

Time of travel  = 5hrs

Average speed  = 500miles/hr

Unknown:

Distance between the two cities  = ?

Solution:

To solve this problem, we must understand that speed is the distance covered with time.

  So;

      Distance  = speed x time

Distance  = 500 x 5 = 2500miles

answer;

d. are made mostly of liquid

explanation;

-the general   composition and structure planets includes; they have a thick gas and liquid layer covering a small,solid core. mostly the gases are hydrogen and helium atmosphere and layers of liquid hydrogen. for instance neptune and uranus are examples of the outer planets, they have a core covered by ice and ammonia.

-neptune's atmosphere is hydrogen and helium with a bit of methane so there is no oxygen to breath and the interior is made up of frozen water and ammonia with a rock and iron core. thus, there is no liquid water or solid surface to survive.