worksheets - Indian Institute of Technology, Bombay

Tejas and Jyoti make a note of the information available and the conditions
of the problem as follows:
I. Task: To make a circular chain.
II. Identify:
1. Goal- Join all the 12 links into a single circle.
2. Information available-
Four pieces of chain.
Each chain has three closed links inter-connected.
The links can be closed and opened.
3. Conditions-
Opening a link or closing a link is counted as one action.
Number of actions to complete the task should not be
more than six.
III. Solve:
(See the next box.)
A
B
C
D
Tejas: Let us open link at the end of chain ‘A’ and
connect it to the beginning link of chain ‘B’.
Jyoti: Then we will open the end link of ‘B’ and
connect it to the beginning link of the chain ‘C’.
Moz: The number of actions are now 4. You have
two more actions to complete the circular chain.
Tejas: Oh! We cannot complete in two more actions
as we still have to connect the ‘D’ chain and then
close the circle. What should we do?
1 2 3
A
Tejas and Jyoti start thinking of other
options and they keep playing with one
chain. Tejas accidentally opens all the links
of chain A.
B
C
Tejas (exclaims): Look! The three links of chain A
D
are open. Let us try connecting other chains B, C and
D with these links.
Jyoti: We have already used three actions for opening the three links of
chain A. We have to achieve the goal with three more actions!
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