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.
What is the perimeter of PQRS ?
(1) x = 30 degree
(2) w= 45 degree
When you modify the condition and the question, you can figure out PQ is an angle of 60 degrees and the length of PQ from QT=2, PT=1. Also, since y=120, you can come up with QS. Thus, you only need to figure out RS, which makes 1 variable. You also need 1 equation in order to match with the number of equations. For 1) 1 equation, for 2) 1 equation, which is likely to make D the answer.
For 1), you already know that x=30, which is not sufficient.
For 2), from w=45, you can figure out the perimeter, which is sufficient. Therefore, the answer is B.
-> For cases where we need 1 more equation, such as original conditions with “1 variable”, or “2 variables and 1 equation”, or “3 variables and 2 equations”, we have 1 equation each in both 1) and 2). Therefore, there is 59 % chance that D is the answer, while A or B has 38% chance and C or E has 3% chance. Since D is most likely to be the answer using 1) and 2) separately according to DS definition. Obviously there may be cases where the answer is A, B, C or E.
_________________