挑战习题
1/5单选题
难度:

1.一件工作,甲队独做10天完成,乙队独做15天完成,若两队合做,则需____天完成.
A 8
B 6
C 10
D 7
提示1:
5bel56iL6Zeu6aKY5LiJ6KaB57Sg77ya5bel5L2c5pWI546Hw5flt6XkvZzml7bpl7Q95bel5L2c5oC76YeP
提示2:
5YiX5pa556iL6Kej5bqU55So6aKY
正确答案:Qg==
6Kej77ya6K6+6ZyA6KaBeOWkqeWujOaIkOOAguWIl+aWueeoi++8jOW+l++8mig8aW1nIHdpZHRoPTYxIGhlaWdodD00MiBzcmM9Imh0dHBzOi8vcDEucWluZ2d1by5jb20vRzEvTTAwLzNFL0JDL3JCQUNKbFRJdF92eklDNG5BQUFCeG04cDQwTTY1Mi5wbmciPil4PTHvvIzop6Plvpd4PTY=