If both M , N are 3 digit numbers and their ratio, N M is an integer. What is the largest possible value of N M ?
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The solution that I was thinking of was 1 0 0 9 0 0 = 9 , but of course there are numerous possibilities.
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How not 10? The largest possible imo should be 999/100 = 9.99 = 10
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9 is the largest integer that is smaller than 9.99.
he said it is integer
That's exactly what I did. The greatest three digit number is 999 and the lowest 100. I feel the correct answer is 10. 999/100 = 9.9 which rounds up to 10! Just saying :)
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@Chelsea Sanchez – In repsonse to both Chelsea and Hassaan, I was going with that too, until I reread the question to see that the answer had to be an integer. Since the question did not allow rounding and 9.99 would not be an integer, the answer had to be 9 as the largest integer that could be created by the stipulations given.
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@Keith Abramowski – Oh. Whoops! Many thanks to Daniel and Keith for clarification. :)
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@Chelsea Sanchez – Actually, now that I think about it, ANY problem given these parameters would come out to "9". If M/N is an integer and both M and N are 5 digit integers, it would still be "9" = 90000/10000 = 9
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@Keith Abramowski – It always will be. A factor of 10 requires, well, a factor of 10.
@Keith Abramowski – That's correct! You should post the 5 digit version of this problem.
@Chelsea Sanchez – Still not an integer. Sure you'd be right if it asked to round to the nearest whole number, but 9.99999<10. So therefore your reasoning is invalid for this particular question.
i did it the same way bro.. Nice solution!!!!!!!
If so, den y nt 8????
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We are looking for the largest integer value of N M , we are not looking for the second largest or third largest or so on.
observe that when you multiply a 3digit number by 10, you get a 4digit number. Therefore, the largest possible value of n m is 9
Great! The 4 digit observation greatly reduces the work that has to be done :)
The biggest 3 digit no=999 The smallest 3 digit no=100 999/100=9.99 Hence, the largest possible value is 9
Right, that's another way to show that the largest value is < 10.
Clear explanation
obviously I agree with his solution
M and N are both 3 digit numbers, so they can range from 100 to 999. The highest possible number for the equation would be 999/100 but that will not equal an integer so you will increase the number to 999/111 and that will equal 9
Perfect! It's rare to see someone from South Africa ,so welcome to the Brilliant community!
100 9=900 this is an example but you can go farther Since 100 is the smallest 3didgit number, 100 10=1000. 1000 is a four digit number. Therefore 9 is the highest
That is an example. How do you know that we cannot go further?
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Oh. I forgot to post the second part. It's: Since 100 is the smallest 3didgit number, 100*10=1000. 1000 is a four digit number. Therefore 9 is the highest
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Yes. Can you add that to your solution? You can edit it by clicking on the edit button.
100<=M<1000 so 2<=logM<3 and 100<=N<100 so 2<=logN<3 or -3<-logN<=-2. Adding theses inequalities gives -1<logM-logN<1 or -1<log(M/N)<1 or 1/10<M/N<10. Since M/N is an integer,1<= M/N<=9. We can easily find examples of M/N=9 (M=900, N=100), but we will search in vain to find an example where M/N=10.
The greatest 3 digit integer is 999 and the smallest is 100. However, because we are looking for integers and also dividing by 100 we know that we can only use exact three digit multiples of 100; the greatest of those multiples being 900. Therefore,
900/100 = 9
Nicely done!
Python 2.7:
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That is beautiful claps
xrange(100,999)
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Actually, the two parameters for xrange are start and stop ; the output will never include stop . Try it.
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I know it's a weird rule, but I think it's designed so that if you use xrange(n) you can have the number of iterations be exactly n. For example...
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...will print 'output' 10 times. The values of i would be [0,1,2,3,4,5,6,7,8,9].
Pythonic solution
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Largest 3 digit no 999 Smalest 111 to have integer ratioo 999/111=9
Divide the largest 3-digit number by the smallest 3-digit number. So, 999÷100=9.
In order to get a possible answer I just devided biggest 3 digit number possible and smallest three digit number possible. Thus, 999/111 =9
Choose the highest possible 3 digit whole number and substitute it for M. So M=999. Then, you need to find what is N. Easy. Just divide 999 by 9. Why 9 for N? Because it's probably the only whole number you can use that will divide 999 without turning the quotient into a decimal number that will keep it a 3 digit number.
M=999 N=111
M/N=999/111
999/111=9
M is 999, and n can be 111
You have only shown that N M = 9 is possible, and you haven't shown that 9 is the maximum value nor did you explain why you chose the values of m , n specifically.
But, why can't the answer be 10?
I just multiplied 3 times 3
This solution has been marked wrong because it fails to show any connection to the problem.
Hm, can you explain why?
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First, note that 9 is a valid possibility when, for example, 9 ∗ 1 1 1 = 9 9 9 .
Any number from 1 0 and beyond, when multiplied by a 3 -digit number becomes a number greater than or equal to 1 0 0 0 , and so N would be a 4 -digit number which would not meet the problem's requirements.