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GATE 2022 EE – Question 3

General Aptitude · Quantitative Aptitude: Arithmetic and Number Computation · 1 mark · Multiple choice

Three bells P, Q, and R are rung periodically in a school. P is rung every 20 minutes; Q is rung every 30 minutes and R is rung every 50 minutes.

If all the three bells are rung at 12:00 PM, when will the three bells ring together again the next time?

  1. 5:00 PM
  2. 5:30 PM
  3. 6:00 PM
  4. 6:30 PM

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Show answer and explanation

Correct answer: (A) 5:00 PM

Explanation

They ring together again after $\text{LCM}(20,30,50)=300$ minutes $=5$ hours, i.e. at 5:00 PM.