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.
Is the hundredths digit of the decimal d great than 5?
1) The tenths digit of 10d is 7.
2) The thousandths digit of d/10 is 7.
There is one variable (d) and 2 equations are given by the conditions, so there is high chance (D) will become the answer.
For condition 1, the hundredth digit of d=7. This is unique and the condition is hence sufficient
For condition 2, the hundredth digit of d=7. This is unique and the condition is hence sufficient
1)=2), and the answer hence becomes (D).
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.
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