SAT Math Multiple Choice Practice Question 492: Answer and Explanation
12. Starting with a blue light, a strand of colored lights contains lights in a repeating pattern of blue, orange, green, purple, red, and yellow. What is the color of the 53rd light?
Correct Answer: E
E Start by writing out the pattern: Blue is the 1st light, orange is 2nd, green is 3, purple is 4, red is 5, and yellow is 6. Then the pattern starts over again, so the 7th light is blue, orange is 8, green is 9, purple is 10, red is 11, and yellow is 12. Notice that the yellow lights go by multiples of 6? The 18th light will also be yellow, as will the 24th, 30th, and so on. We want to know the 53rd, so the closest light we know to 53 is the 54th light, which is yellow. If the 54th is yellow, then the light immediately before is the 53rd, which must be red, answer E.