summer1350 Posted September 28, 2010 Share Posted September 28, 2010 Can anyone please help me with the following question: An electronic device makes beep every 60 sec. Another device makes a beep after every 62 sec. They beep together at 10 AM. The time when they will next make a beep together at the earliest is: A) 10.30 AM B) 10.31 AM C) 10.59 AM D) 11 AM E) 11.05 AM Quote Link to comment Share on other sites More sharing options...
sueka Posted September 28, 2010 Share Posted September 28, 2010 LCM of 60 and 62 is 1860 In ither words, after 1860 seconds the two clocks will beep together. Let's convert this to minutes 1860 / 60 = 31. Next time the two clocks will beep together = 10 am + 31 min = 10.31 AM Quote Link to comment Share on other sites More sharing options...
summer1350 Posted September 28, 2010 Author Share Posted September 28, 2010 Thank you :) Quote Link to comment Share on other sites More sharing options...
eslim Posted October 7, 2010 Share Posted October 7, 2010 I need your help in the following question, under what topics is this question ? If 5 men can make 40 tables in 12 days, calculate how long it will take 24 men to make 320 tables ? Quote Link to comment Share on other sites More sharing options...
osmias Posted October 7, 2010 Share Posted October 7, 2010 The question comes under ratios and proportions. Solvin them is very simple by the following method: Make a table according to the question and then form an equation by that table. The table should be as below: MEN DAYS TABLES 5 12 40 24 x 320 To form an equation, first hide the tables part and consider men and days only. You see that the no. of men are increasing, therefore, no. of days should decrease if the no. of tables are the same or constant. This forms an inversely proportion relationship between the men and days. This means that 5 will multiply by 12 and x will multiply by 24. Your equation will be (5)(12)( ) = (x)(24)( ) (Note that the empty spaces are for the next relation between days and tables. Secondly, if the relation would have been directly proportional, then 5 would multiply by x and viceversa) Now forget the mens portion or keep it constant, if the no. of tables increase, the no. of days would also increase i.e. a direct relationship thus, (5)(12)(320)=(x)(24)(40) or x=20 days HOPE THAT HELPS Quote Link to comment Share on other sites More sharing options...
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