distances between planets

Question

If planet 1 is 33.8 million miles farther from the sun than planet 2,then planet 3 is 23.9 million miles farther from the sun than planet1. when the total of the distances for these 3 planets from the sun is 190.5 million miles,how far away from the sun is planet 2?

Answer 1

Let the distances in millions of miles of the three planets be P1, P2, P3.

P1=P2+33.8; P3=P1+23.9=P2+57.7;

P1+P2+P3=190.5, P2+33.8+P2+P2+57.7=190.5,

3P2+91.5=190.5, 3P2=99, P2=33 million miles from the sun.

Note that the distances between the planets varies depending on where they are in their orbits.