求教：GWD-6 数学 Q7

ursula1102

Q7:
A certain university will select 1 of 7 candidates eligible to fill a position in the mathematics department and 2 of 10 candidates eligible to fill 2 identical positions in the computer science department.If none of the candidates is eligible for a position in both departments, how many different sets of 3 candidates are there to fill the 3 positions?


A.42
B.70
C.140
D.165
E.315
答案： E
这题没读太明白，我算是组合C(1,7) 乘以C(2,10)，可是没有答案~

serenashu

楼主你在算一遍~~就是你那样做的

dinglovejay

没错阿 7x45=315