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.

In the rectangular coordinate system, line k is defined by the equation x - 2y + n = 0. What is the value of n?

(1) The x-intercept of line k is 8.

(2) The y-intercept of line k is -4.

There are 2 variables (m,n) in y=mx+n, but actually, we only need to know n in order to understand the graph, so we only have one variable (n). There are 2 equations given, so there is high chance (D) is our answer.

For condition 1, it passes through (8,0), 8-2*0+n=0, n=-8. This is sufficient.

For condition 2, is passes through (0,-4), and from 0-2(-4)+n=0, n=-8. This is sufficient as well, making the answer (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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