95 views
The least number of five digits which is exactly divisible by 12,15 and 18 is:

a)10080 b)10800 c)18000 d)81000
| 95 views
+2
if you have options, then check directly which numbers are divisible by LCM(12,15,18)

among them choose the lowest number, ( option A is right for this question )
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@Shaik Masthan,Tysm Brother. :). You've given the right clue.
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Brother, actually this is not good method, to know the concept !

This is just a method for multiple choice only...

+1 vote
The LCM of the three numbers is 180.

Now, 180 x 50 is 9000, 180 x 60 is 10800.

So the number has to lie between 10000 and 10800.

Now, 180 x 55 = 9900, 180 x 56 = 10800.

So the answer should be 10800

180 x 56 is 10080, not 10800.
by Loyal (6.7k points)
edited
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@goxul,Brother the answer is option a)  actually. :)
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@goxul,Brother don't take me in wrong way but I'll suggest you to please follow the method suggested by Shaik Masthan brother. Okay. Hope it helps. :)
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Oh lol, I made a typo.

180 x 56 is 10080, my bad.
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No issues. You've corrected. That's wat matters. :)
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@goxul,It sounds cool though the method you shared. You kinda created a range b/w 50 and 60. It's obvious 9000 being nearer and 10800 being the upper limit. How did you deduced 55 and 56 btw?
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@goxul,@Shaik Masthan,We now have two methods. Woah good job both of you. :)
+1
Well, its easy to see that 180*50 is 9000 and 180*5 is 900.

So, 180*55 becomes 9900 and since this is the closest to 10000, the next multiple has to be the smallest one which is divisible by all of them.
try option A and it is the least among all the options and it is exactly divisible by 12,15 and 18 , for your convenience you can try it with GATE VIRTUAL CALCULATOR , and the logic of try it with LCM of 3 will also work , option elimination will be the best approach here
by (249 points)

+1 vote