An arithmetic progression is a sequence in which the difference of any

Forget conventional ways of solving math questions. In DS, Variable approach is the easiest and quickest way to find the answer without actually solving the problem. Remember equal number of variables and independent equations ensures a solution.

An arithmetic progression is a sequence in which the difference
of any two successive numbers of the sequence is a constant.
For example, { 4, 8, 12, 16 } is an arithmetic progression in
Which the difference of any two successive numbers is 4.
Is the infinite sequence S an arithmetic progression?

(1) For any term n in S, Sn = Sn-1 + 2

(2) Each term in S is a positive odd integer.


In the original condition, it says difference amongst each term of the arithmetic progression is constant and asks if sequence S is an arithmetic progression.
For 1), the difference is 2, which is yes and sufficient.
For 2), it doesn’t say consecutive, which is not sufficient.
Thus, the answer is A.


 Once we modify the original condition and the question according to the variable approach method 1, we can solve approximately 30% of DS questions.

Here Statement 1 is sufficient as The difference between successive terms is always being constant.
However statement 2 is not as the odd integers can be 1,101,103 ..or 1,3,5
hence A is sufficient

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