In November last year, after 10 years of "chasing stars", human probes successfully landed on a comet 500 million kilometers away from the earth. The distance from the earth to the sun is 0.25 billion kilometers less than the distance to the comet (7/20). How many billion kilometers is the distance from the earth to the sun?
去年11月，经过10年的"追星"，人类探测器成功着陆距地球5亿km的彗星．地球到太阳的距离比到彗星的距离的(7/20)还少0.25亿km，地球到太阳的距离是多少亿千米？
<gadget id="calculator">7 / 20</gadget>
<output>7/20 = around 0.35</output>

<gadget id="calculator">5 * (7/20)</gadget>
<output>7/4 = around 1.75</output>

<gadget id="calculator">(7/4) - 0.25</gadget>
<output>1.5</output>

<result>1.5</result>