Ease Into Prep with an SAT^® Question of the Day

Picking numbers can make abstract questions like this more manageable. Say that the train is scheduled to arrive in x = 10 minutes. It will actually arrive within 5 minutes of this time, so it will arrive somewhere between 5 and 15 minutes. Plug x = 10 and any number between 5 and 15 (say, y = 6) into each answer choice and see which ones can be eliminated:

(A) |5 − 6| = 10
(B) |6 −5| ≥ 10
(C) |6 − 10| ≤ 5
(D) |10 − 6| ≥ 5
Choice (C) is correct.

You could also think about this algebraically. If the train is 5 minutes late, then y = x + 5, or y - x = 5. If the train is 5 minutes early, then y = x − 5, or y - x = −5. Therefore, y - x = ±5. This is equivalent to |y − x| = 5. Choice (C) is correct.