Chain Making Puzzle

Chain Making Puzzle:



There are 5 metal rings...

I want to join them and make a chain as shown in the image.

It involves cutting and welding(joining) the metal rings.

Cutting the ring cost Rs10/- for each cut.
Welding the ring cost Rs20/- for each join.

What is the minimum cost to make the chain ?

Solution:

Answer:
The minimum cost is Rs.60

Explanation:
We only need to cut and weld the 2nd and 4th ring.
So cutting cost Rs.10 = 2 x 10 = Rs.20
Welding cost Rs.20 = 2 x 20 = Rs.40

Hence Total cost = 20+40 = Rs.60