小红抄一份稿子要1/4小时,小明抄同样的稿子要1/3小时.两人合抄这份稿子要几小时?
A:1/(4+1/3)B:2/(1/4+1/3)
C:1/(1/4+1/3)D:1/(1/1/4+1/3)
D:1/(1/1/4+1/1/3)
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