![](https://static.youtibao.com/asksite/comm/h5/images/m_q_title.png)
[单选题]
某次知识竞赛共有20道题,规定:每答对一道题得+,每答错一道题得﹣,不答的题得,已知圆圆这次竞赛得了,设圆圆答对了x道题,答错了y道题,则()
A.x﹣y=20
B.x+y=20
C.5x﹣2y=60
D.5x+2y=60
![](https://static.youtibao.com/asksite/comm/h5/images/m_q_a.png)
C、5x﹣2y=60
![](https://static.youtibao.com/asksite/comm/h5/images/solist_ts.png)
A.x﹣y=20
B.x+y=20
C.5x﹣2y=60
D.5x+2y=60
C、5x﹣2y=60
A.5x﹣3(30﹣x)>70
B.5x+3(30﹣x)≤70
C.5x﹣3(30+x)≥70
D.5x+3(30﹣x)>70
A.10x-5(20-x)≥90
B.10x-5(20-x)>90
C.10x-(20-x)≥90
D.10x-(20-x)>90
A.7/8
B.6/7
C.3/5
D.1/3
A.18
B.21
C.25
D.36
A.0
B.5
C.7
D.9