Four bells ring simultaneously at starting and an interval of 6 sec, 12 sec, 15 sec and 20 sec respectively. How many times they ring together in 2 hours?
A120
B60
C121
D112
Answer:
C. 121
Read Explanation:
LCM of (6, 12, 15, 20) = 60
All 4 bells ring together again after every 60 seconds
In 2 Hours, they ring together = [(2 × 60 × 60)/60] times + 1 (at the starting) = 121 times
