If one manuscript is typed alone, A needs to finish typing by 4 o'clock, and B can finish typing this manuscript by 2 o'clock (1/6). If two people cooperate, how long can they finish typing this manuscript?
单独打一份稿件，甲要4时打完，乙2时能打了这份稿件的(1/6)，如果两人合作，多少时能够打完这份稿件？
<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 / 6</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">(1/6) / 2</gadget>
<output>1/12 = around 0.083333</output>

<gadget id="calculator">(1/4) + (1/12)</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 / (1/3)</gadget>
<output>3</output>

<result>3</result>