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# help

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A number is formed by writing the numbers 1 to 30 in order as shown.

12345678910111213..........2930

Simeon removed 45 of these 51 digits leaving 6 in their original order to make the largest 6-digit number possible. What is the this number?

Nov 27, 2019

#1
+1

n=123456789101112131415161718192021222324252627282930;s=0;p=0;cycle: s=s+(n%10);p=p+1;n=int(n/10);if(n!=0, goto cycle,0);print"Total Sum =",s;print"Total Num =",p

920,212 - is the largest such number.

Nov 27, 2019

#1
+1

n=123456789101112131415161718192021222324252627282930;s=0;p=0;cycle: s=s+(n%10);p=p+1;n=int(n/10);if(n!=0, goto cycle,0);print"Total Sum =",s;print"Total Num =",p

920,212 - is the largest such number.

Guest Nov 27, 2019
#2
-1

We want the earliest digits to be the biggest. Let's start with 9 since that's the biggest number.

9_____

Now, the only numbers left we can use are 10, 11, 12, etc. all the way to 30.

30 is the biggest one, so let's use that next.

930___

BUT WAIT! There are no digits greater than 30. So let's do 29.

929___

Then 30

92930_

Here, we run into a problem. The last digit must be a single digit, but there is no single-digit remaining.

If we choose two one-digit numbers in the beginning, then it will work out.

Obviously, 8 and then 9 is the best option.

89____

Then, since 30 cannot be used after these two numbers, we must use 29 and then 30.

You are very welcome!

:P

Nov 27, 2019
#3
0

CoolStuff: Where does your number 892930 appear in the above sequence "leaving 6 in their original order"?

Nov 27, 2019