The Gateway to Computer Science Excellence
0 votes
The project of building $20$ roads connecting $9$ cities is under way, as outlined above. So far, only some of the $20$ roads are constructed, and the digit on each city indicates the number of constructed roads to other cities. How many complete roads are there among these cities _____?
in Unknown Category by Junior | 137 views

@Applied Course Please edit the question. Diagram is missing.

1 Answer

+1 vote
Applied Course 2019 Mock1-37
Let $V$ be the degree of each node and $E$ be the number of edges in the graph. As such, each digit on each city is $V$, and the number of roads will be $E$. The sum of all degrees will equal twice number of edges:
$\Sigma V=2E$
Therefore $2E=1+1+1+2+2+3+3+4+5 = 11$
There are $11$ complete roads among these cities.
The road map with red complete tracks can be illustrated as seen below:
Applied Course 2019 Mock1-37
by Junior
Shouldn't a diagram be given in the question?
I think, Diagram should be given

Related questions

Quick search syntax
tags tag:apple
author user:martin
title title:apple
content content:apple
exclude -tag:apple
force match +apple
views views:100
score score:10
answers answers:2
is accepted isaccepted:true
is closed isclosed:true
52,218 questions
59,895 answers
118,134 users