Use the following information to answer questions 30–33.
The chart below provides some facts about 4 planets in our solar system.
*The strength of surface gravity refers to the gravitational acceleration of an object near the surface of the planet. The values given are percents of 32.2 ft/sec2 (feet per second per second), which is the gravitational acceleration of an object near the surface of Earth.
30. What is the positive difference between the given values of average distance from the Sun for Mars and for Mercury?