Four lights light up simultaneously at starting and an interval of 6 sec, 12 sec, 15 sec and 20 sec respectively. How many times do they light up together in 2 hours?
1
120 times
2
121 times
3
191 times
4
118 times
Four lights light up simultaneously at starting and an interval of 6 sec, 12 sec, 15 sec and 20 sec respectively. How many times do they light up together in 2 hours?