Bissoy.com
Doctors Medicines MCQs Q&A

At a telephone exchange, three phones ring at intervals of 20 sec, 24 sec and 30 seconds - If they ring together at 11:25 am, when will they next ring together?

At a telephone exchange, three phones ring at intervals of 20 sec, 24 sec and 30 seconds - If they ring together at 11:25 am, when will they next ring together? Correct Answer 11:27 am

Time taken by three phones to ring together = LCM of 20, 24 and 30

⇒ Time taken by three phones to ring together = 120 seconds

(∵ 1 min = 60 seconds)

⇒ Time taken by three phones to ring together = 120/60 = 2 min

If the three phones ring together at 11:25 am then they will next ring together after 2 minutes i.e. at 11:27 am.

∴ Time at which the phones next ring together = 11:27 am

Related Questions

At a telephone exchange, three phones ring at intervals of 20 sec, 24 sec and 30 seconds. If they ring together at 11 : 25 a.m, when will they next ring together?
Rajeev visited an electronic gadgets store to buy Mobile phones and Laptops. He purchased 2 mobile phones and 1 laptop. For this purchase, he paid full amount of the Mobile phones but only one-third of the amount of the Laptop. In total he paid Rs. 60,000. After a week, he visited the store again and purchased 3 Mobile phones and 2 Laptops. For this purchase, he paid full amount of the Laptops but only two-third of the amount of the Mobile phones. This time he paid Rs. 1,10,000 in total. What amount he should pay if he purchase 1 Mobile phone and 1 Laptop only and pays full amount for both ?
Two bells ring at intervals of 63 seconds and 74 seconds. If they both ring at 10 O'clock in the morning together, after how many seconds will they ring together again?
Two bells ring at intervals of 51 seconds and 62 seconds. If they both ring at 10 O'clock in the morning together, after how many seconds will they ring together again?
Two bells ring at intervals of 59 seconds and 70 seconds. If they both ring at 10 O'clock in the morning together, after how many seconds will they ring together again?
Two bells ring at intervals of 78 seconds and 46 seconds. If they both ring at 10 O'clock in the morning together, after how many seconds will they ring together again?
Two bells ring at intervals of 88 seconds and 58 seconds. If they both ring at 10 O'clock in the morning together, after how many seconds will they ring together again?
There are 35 mobile phones in a box, out of which the average weight of 12 mobile phones is 50 grams and the average weight of 11 mobile phones is 40 grams and the average weight of the remaining mobile phones is 45 grams, then find the average weight of all mobile phones. (approx.)
Five phones, H, M, R, T and V, are kept one above the other (not necessarily in the same order). The number of phones above T is same as the number of phones below V. R is just above H. V is at the bottom. There are two phones between M and V. Which of the following phones are above R?
The given question consists of three statements numbered I, II and III. You have to decide whether the data provided in the statements are sufficient to answer the question. Read all the statements and answer the question. What will be the sum of the number of mobile phones sold by Samsung and Apple together after 7 years? I. Samsung’s present product sale is four times that of Apple present sale. II. After 14 years, the ratio of number of phones sold by Samsung to Apple will become 24 ∶ 19. III. The difference between the number of mobile phones sold by Samsung and Apple was equal to the number of phones sold by Apple.