Problema Solution
The media center of a college runs videotapes of two lectures continuously. One videotape runs for 42 minutes and a second runs for 56 minutes. Both video tapes begin at 9:00 am. When will the videos of the 2 lectures begin again at the same time?
Answer provided by our tutors
The prime factor form of 42 and 56
42 = 2*3*7
56 = 2*2*2*3*7
The least common multiple must have each of the
prime factors in their highest power.
lcm = (2*2*2)*3*7 = 168
Therefore, the video tapes will start at the same time again after 168 minutes or 2 hours 48 minutes.
The time will be, 11:48am.