car drives from A to B at a speed of 100 kilometers per hour and arrives 1 hour earlier than originally planned; it arrives 1 hour later than originally planned at a speed of 60 kilometers per hour from A to B; How many hours do you plan to drive.
一辆汽车用每小时100千米的速度从甲地开到乙地，比原计划提前l小时到达；用每小时60千米的速度从甲地开到乙地比原计划迟到1小时；原计划开多少小时．
<gadget id="calculator">100 * 1</gadget>
<output>100</output>

<gadget id="calculator">60 * 1</gadget>
<output>60</output>

<gadget id="calculator">100 + 60</gadget>
<output>160</output>

<gadget id="calculator">100 - 60</gadget>
<output>40</output>

<gadget id="calculator">160 / 40</gadget>
<output>4</output>

<result>4</result>