Question

There are three street lights which get on for one second after 30 s, 40 s and 50 s, respectively. If last time they were on simultaneously at 04:00 PM. At what time after 04:00 PM all of them get on again simultaneously?

• A. 04:10 PM
• B. 04:11 PM
• C. 04:12 PM
• D. 04:14 PM

Answer 1

Answer:

A. 04:10 PM

LCM of 30, 40 and 50 = 600 s The street light get simultaneously on after 600 s i.e. 600/60 = 10 min