Greatest number

[Mohit Pandey]

Find the greatest number of four digits which when divided by 3,5,7,9 leaves remainders 1, 3, 5, 7 respectively.

[eric l]

Do you just want the result, or do you want to know the way to find it ?

[Mohit Pandey]

Do you just want the result, or do you want to know the way to find it ?

 

I want to know the way to find solutions to such kinds of question.

[eric l]

I want to know the way to find solutions to such kinds of question.

This one is relatively simple, because the remainders are each time the (dividers - 2).

So the smallest nummber that gives these results will be the least common multiple - 2. Why ? If the remainders were 2 units higher, the number in question would be a multiple of all these dividers.

The least common multiple for 3, 5, 7 and 9 is 315.

Now divide 9999 (the greatest 4 digit number) by 315, and multiply 315 by the integer part of the quotient. You get 9999/315 = 31.74.

315 * 31 = 9765. This - 2 gives 9763

 

If will be a little more complicated if your remainders do not have something in common like in this case, but still : if you go up the list of numbers, each time you are (least common multiple) units farther, you have the same dividers.

 

By the way, don't ask us to make your homework every week.

[Mohit Pandey]

Thank you for clearing my doubts.

Posted by eric l:By the way, don't ask us to make your homework every week.

I am not asking questions from my homework. This question was asked in an Maths Examination.

I always ask question when the idea or concept behind the question is not clear in my mind. Guys like you on this website help me to grasp the concept. Thank you again. :eek_big:

[CraigD]

I am not asking questions from my homework. This question was asked in an Maths Examination.

I always ask question when the idea or concept behind the question is not clear in my mind. Guys like you on this website help me to grasp the concept. Thank you again. :)

Helping is a big part of what hypography is about – I’m glad you find the people here helpful, Mohit. :) :confused:

 

Eric’s point, though, has merit. School-related work – whether actual assigned homework, exam follow-up, etc, should be posted in the Science Projects & Homework forum. Even independent study of academic textbook material often fits best in this forum. This allows people to be clear on the nature and intention of the thread, which is helpful to everyone. It prevents people from taking a question as a contest-like challenge and just answering it, which isn’t a very good way to help with class-related work, and allow people who like providing such help to go straight to it, and people who prefer not to to avoid it.

 

If you – or anyone – have any question about the forums, please don’t hesitate to ask, either via a PM to me or another moderator, or in Tutorial and how-tos, feedback, or a similar forum.

[Mohit Pandey]

Helping is a big part of what hypography is about – I’m glad you find the people here helpful, Mohit....................................

If you – or anyone – have any question about the forums, please don’t hesitate to ask, either via a PM to me or another moderator, or in Tutorial and how-tos, feedback, or a similar forum.

This makes Hypograhy different from others. :confused: