GloryBoy92 wrote:

Is X > 1 ?

1. 1/x > 1

2. x > 0

Forget conventional ways of solving math questions. For DS problems, the VA (Variable Approach) method is the quickest and easiest way to find the answer without actually solving the problem. Remember that equal numbers of variables and independent equations ensure a solution.

Visit

https://www.mathrevolution.com/gmat/lesson for details.

Since we have 1 variable (\(x\)) and 0 equations, D is most likely to be the answer. So, we should consider each condition on its own first.

Condition 1)

We should simplify a condition if necessary.

\(\frac{1}{x} > 1\)

\(⇔ x > x^2\) by multiplying by x^2 since x^2 is positive

\(⇔ x^2 - x < 0\)

\(⇔ x(x-1) < 0\)

\(⇔ 0 < x < 1\)

Since 'no' is also a unique answer by CMT (Common Mistake Type) 1, condition 1) is sufficient, when used together.

Condition 2)

In inequality questions, the law “Question is King” tells us that if the solution set of the question includes the solution set of the condition, then the condition is sufficient.

However, since the solution set \(x > 1\) does not include the solution set \(x > 0\) of condition 2, condition 2) is not sufficient.

If the original condition includes “1 variable”, or “2 variables and 1 equation”, or “3 variables and 2 equations” etc., one more equation is required to answer the question. If each of conditions 1) and 2) provide an additional equation, there is a 59% chance that D is the answer, a 38% chance that A or B is the answer, and a 3% chance that the answer is C or E. Thus, answer D (conditions 1) and 2), when applied separately, are sufficient to answer the question) is most likely, but there may be cases where the answer is A,B,C or E.

Thanks for the answer, I'm curious as to why the lecturer in your video gave a different answer