A planet orbits the Sun in a time T at a distance of R from it. Another planet orbits the Sun in a time of 8T. What is its distance R' from the Sun.?

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Planet Nine. Planet Nine orbits the sunat a distance that is 20 times farther out than the orbit of Neptune. (Theorbit of Neptune is 2.7 billion miles from the sun at its closest point.) The strange world's orbit is about 600times farther from the sun than theEarth's orbit is from the star.