CAT 1991 — QA Question 43
Answer the following questions based on the information given below:
There were a hundred schools in a town. Of these, the number of schools having a play – ground was 30, and these schools had neither a library nor a laboratory. The number of schools having a laboratory alone was twice the number of those having a library only. The number of schools having a laboratory as well as a library was one fourth the number of those having a laboratory alone. The number of schools having either a laboratory or a library or both was 35.
In a six-node network, two nodes are connected to all the other nodes. Of the remaining four, each is connected to four nodes. What is the total number of links in the network?
Answer & solution
13
- B
15
- C
7
- D
26
Nodes 1 & 2 will be connected with 5 links each hence, we get 10 links
Nodes 3, 4, 5, and 6 will be connected witih 4 links each hence, we get 16 links.
Total links = 10 + 16 = 26.
Now since each link connects 2 nodes, unique number of links = 26/2 = 13.
Alternately,
(Note : In the diagram given below, the top two nodes are connected to all the other nodes, while the remaining four are connected to only four other nodes).
You find that the total number of links in the network is 13.
Hence, option (a).