0 0 votes A red light flashes $3$ times per minute and a green light flashes $5$ times in two minutes at regular intervals. If both lights start flashing at the same time, how many times do they flash together in each hour? $30$ $24$ $20$ $60$ Quantitative Aptitude cat2001 quantitative-aptitude lcm-hcf + – go_editor 14.2k points 3.2k views answer comment Share Follow Print 0 reply Please log in or register to add a comment.
Best answer 1 1 vote Red light flashes 3 times per min (once every 20 sec) Green light flashes 5 times per 2 min (once every 24 sec) For flash together together=LCM of (20 & 24) => together once every 120 sec No. of flashes in each hour =$\frac{3600}{120}=30$ Hence,option (1)30. Leen Sharma answered May 9, 2016 • edited May 14, 2016 by Leen Sharma Leen Sharma 11.6k points comment Share Follow See all 2 Comments 2 2 Comments reply minal 2.3k points commented May 14, 2016 reply Follow flag red light flash once every 20 sec rt 1 1 replyShare Leen Sharma 11.6k points commented May 14, 2016 reply Follow flag yes,its 20 sec.I did right but by mistake i wrote 30 sec.Thank You. :) 1 1 replyShare Please log in or register to add a comment.
