(英文)麻烦解释原因.Amy has to visit towns B and C in any order. The roads connecting these towns with her home are shown on the diagram. How many different routes can she take starting from A and returning to A, going through both B and C
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(英文)麻烦解释原因.Amy has to visit towns B and C in any order. The roads connecting these towns with her home are shown on the diagram. How many different routes can she take starting from A and returning to A, going through both B and C
(英文)麻烦解释原因.
Amy has to visit towns B and C in any order. The roads connecting these towns with her home are shown on the diagram. How many different routes can she take starting from A and returning to A, going through both B and C (but not more than once through each) and not travelling any road twice on the same trip?
(英文)麻烦解释原因.Amy has to visit towns B and C in any order. The roads connecting these towns with her home are shown on the diagram. How many different routes can she take starting from A and returning to A, going through both B and C
①顺时针绕椭圆一圈
②逆时针绕椭圆一圈
③将弧AC换为向椭圆内凸的路线,顺时针
④路线同上,逆时针
⑤将弧CB换为向椭圆内凸的路线,顺时针
⑥路线同上,逆时针
⑦将弧AC、BC均换为向椭圆内凸的路线,顺时针
⑧路线同上,逆时针
综上,There're 8 different routes that she can take.
我理解的意思就是从A~B~C~A一共有几条不同的路线,我设的是先到C再到B,
那是有5条,因为先到B再到C走法一样,所以都给排除掉了。
8条
There are four routines for her to spin counterclockwise around the circle.
1.AC(outside)-CB(outside)-BA
2.AC(outside)-CB(inside)--BA
3.AC(inside)--CB(inside)--BA
4.AC(inside)--CB(...
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There are four routines for her to spin counterclockwise around the circle.
1.AC(outside)-CB(outside)-BA
2.AC(outside)-CB(inside)--BA
3.AC(inside)--CB(inside)--BA
4.AC(inside)--CB(outside)--BA
There are four routines for her to go clockwise around the circle.
1.AB-BC(outside)-CA(outside)
2.AB-BC(inside)-CA(outside)
3.AB-BC(outside)-CA(inside)
4.AB-BC(inside)-CA(inside)
In conclusion,we can say there are 8 routines for her from A retuning to A .
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