GRE Quantitative Comparison Question Official Guide Question UrduHindi
This question is taken from ETS guide.
n is a positive integer, x = 7n + 2, and y = 6n + 3.
The ones digit of x + y
In the question, you are given that x = 7n + 2 and y = 6n + 3. Substituting the given expressions for x and y in Quantity A, you get x + y = 13n + 5.
Using trial and error, you can compare Quantity A, the ones digit of 13n + 5, and Quantity B, 5, by plugging in a few values for the positive integer n.
If n = 1, then x + y = 18 and the ones digit is 8, which is greater than 5. So in this case Quantity A is greater than Quantity B.
If n = 2, then x + y = 31 and the ones digit is 1, which is less than 5. So in this case Quantity B is greater than Quantity A.
Since in one case Quantity A is greater than Quantity B, and in the other case Quantity B is greater than Quantity A, you can conclude that the correct answer is Choice D.