Home | Number Concept | Integers | Additional Investigations | Turning Red

Turning Red

Two traffic lights turn red together at exactly 5:00 p.m. One light is on a 36-second cycle from red back to red, and the other is on a 48-second cycle. At what time will they again turn red together? Give the exact time including seconds.

(Source: Adapted from Mathematics Teaching in the Middle School, Feb 1997)

Submit your idea for an investigation to InterMath.