# H.C.F and L.C.M- Aptitude Questions and Answers - in Hindi

 Three wheels can complete 60, 36, 24 revolutions per minute respectively. There is red mark on each wheel that touches the ground at time zero. After how much time, all these spots will simultaneously touch the ground again? तीन पहिये प्रति मिनट क्रमशः 60, 36 और 24 चक्कर पूर्ण कर सकते है । प्रत्येक पहिये पर एक लाल निशान है जो कि प्रारंभ में सतह को स्पर्श करता है । कितने समय के पश्चात ये निशान दोबारा एक साथ सतह को स्पर्श करेगे? A) 2.5 second B) 1.6 second C) 5 second D) 7.5 second Correct Answer : 5 second Explanation :The first wheel spins at 60 rpm which means that it completes 60/60 = 1 revolution every second. The second wheel spins at 36 rpm. So it completes 36/60 = 0.6 of a revolution every second The third wheel spins at 24 rpm. So it completes 24/60 = 0.4 of a revolution every second. So we have the values: 1, 0.6, 0.4 If we wait 10 seconds, then we multiply each value by 10 to get: 10, 6, 4 Now we can divide by the GCF 2 to get 5, 3, 2 This means that it will take 5 seconds for the spots to line up again (since the first number corresponds to the amount of time that has gone by in seconds) Post/View Answer Post comment Cancel Thanks for your comment.! Write a comment(Click here) ...