CAT Question of the Week - 88 Days to CAT 2015

Q. In an industry there are four production processes required to form a metal ball–Forming, Welding, Cutting and Bending—which happen one after the other, not necessarily in this order.
The people working in the industry belong to three different tribes: Laho, Maho and Jaho. People from the Laho tribe always tell the truth. People from the Maho tribe always lie and people from the Jaho tribe always alternate between truth and lies, not necessarily in that order.
Of the four persons, Arun, Varun, Tarun and Karun, one belongs to the Laho tribe and one to the Maho tribe. The others belong to the Jaho tribe. The first statement of one member of the Jaho tribe is true, while that of the other is false. Given below are statements made by these four persons when asked about the production process.

Arun: Cutting is the third process. 
I am from the Jaho tribe. 
Forming is the second process.

Varun: Welding is the second process.
Karun belongs to the Maho tribe. 
Bending is the third process.

Tarun: Forming is the fourth process. 
I am from the Laho tribe. 
Cutting is the first process.

Karun: Bending is the second process. 
I belong to the Laho tribe. 
Cutting is the second process.

 1. Who among the following belongs to Laho tribe?
(A) Arun (B) Varun (C) Tarun (D) Karun

2.  What is true about the tribe to which Tarun belongs?
(A) Laho tribe (B) Maho tribe (C) Jaho tribe whose first statement is false (D) Jaho tribe whose first statement is true

3.   Which is the correct order of the production process?
(A) Bending, Welding, Cutting, Forming
(B) Cutting, Welding, Bending, Forming  
(C) Welding, Cutting, Bending, Forming
(D) Cutting, Forming, Welding, Bending

Solution:
Karun’s statements (1) and (3) cannot be simultaneously true, so his statement (2) is also false. Karun is a liar. He belongs to the Maho tribe.
Since Karun is from the Maho tribe, Arun can be from either the Laho tribe or the Jaho tribe. But if he is a truth-teller, then his second statement will be false and hence contradictory. So, Arun is an alternator and since his second statement becomes true, the first and third statement becomes false.
Also since Karun is from the Maho tribe, Varun’s statement (2) becomes true. But he cannot be an alternator as Arun has made false-true-false (combination) statement. So, Varun is a truth- teller. 
So, Tarun becomes an alternator with true-false-true combination statements.

                         Arun    Varun    Tarun    Karun
Statement 1      F          T           T           F
Statement 2      T          T           F           F
Statement 3      F          T           T           F

Sequence of the production process
Cutting, Welding, Bending, Forming

Ans:
1. Choice(B) Varun belongs to the Laho tribe of truth tellers
2. Tarun belongs to the Jaho tribe Choice(D) and starts with a true statement.  
3. Choice (B) shows the correct sequence of production.