- A31
- B30
- C60
- D15
Step-by-Step Solution
LCM(5, 6, 8, 12) = 120 s, so they coincide every 2 minutes. In 3600 s that is 3600 ÷ 120 = 30 more times, plus the first: 31.
Answer: A) 31
Four bells ring at intervals of 5, 6, 8 and 12 seconds. They ring together at the start. How many times in one hour do they ring together, counting the first?
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