To build a road, the first half of the road needs to be repaired 60 meters per day. If the entire road is to be repaired at an average of 70 meters per day, how many meters should the second half of the road be repaired per day?
修一条路，前半段路每天修60米，若想整条路平均每天修70米，那么后半段路每天需修多少米．
<gadget id="calculator">1 / 35</gadget>
<output>1/35 = around 0.028571</output>

<gadget id="calculator">1 / 60</gadget>
<output>1/60 = around 0.016667</output>

<gadget id="calculator">(1/35) - (1/60)</gadget>
<output>1/84 = around 0.011905</output>

<gadget id="calculator">1 / (1/84)</gadget>
<output>84</output>

<result>84</result>