PRJAN15A - An Arithmetic Problem

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A sequence is an arithmatic sequence if every two succesive number has same difference. Suppose this is a sequence of numbers:


a1, a2, a3,


This is an arithmatic sequence if ai-ai+1 is same for each i from 1 to n-1.


You are given first 3 terms of a sequence and the value of n. If it is an arithmatic sequence you must print the nth term. Otherwise you must print “Error”.


Input Format:

In First line there will an integer T denoting number of test cases. Each of the next 3 lines will contain 4 integers a1, a2, a3 and n.


Output Format:

In each line specify the case number and print the answer.



-300<=a1, a2, a3<=300



Sample Input:


1 2 3 10

1 4 3 10

15 30 45 5


Sample Output:


Case 1: 10

Case 2: Error

Case 3: 75


Problem-setter: Shafaet Ashraf

hide comments
Mitch Schwartz: 2015-01-31 05:04:48

Moved to tutorial, it is very simple.

The correct spelling is "arithmetic".

Sachin Verma: 2015-01-31 05:04:48


Last edit: 2015-01-29 17:48:28
Namit Agrawal: 2015-01-31 05:04:48

it must be a tutorial question..!!

vishrut mishra: 2015-01-31 05:04:48

it should be tutorial

Vamsi Krishna Avula: 2015-01-31 05:04:48

tutorial problem(?)

Added by:Shafaet
Time limit:1s
Source limit:50000B
Memory limit:1536MB
Cluster: Cube (Intel G860)
Languages:All except: ASM64 JS-MONKEY
Resource:Progrkriya Contest January 2015