+ 15

# Quizz time VII 10 digit integer

I have 10 digit integer then i multiply it with 1 digit integer the result is 10 digit integer but in reversed order. Question What is my number? You can use any tool or any programming language. (so far i get 2 answer i think i'll get the third)

33 Answers

+ 17

1089001089 * 9 = 9801009801
1098910989 * 9 = 9890198901
1099999989 * 9 = 9899999901

+ 14

There are quite a number of answers, with two conditions.
The number is a palindrome, and the 1 digit integer is 1. E.g.
1234554321 * 1 = 1234554321
2143553412 * 1 = 2143553412
and so on.
If you exclude these answers, I'll need a desktop compiler. Currently out on the streets.

+ 13

Here's my brute force attempt:
https://code.sololearn.com/cwfK5CJelLhy/?ref=app

+ 13

I used a calculator to check they were correct...
P.S. I wouldn't bother running my code. It takes forever and ever

+ 11

I actually made this little something too. But I can't run it on desktop yet for some very, stupid, reasons.
https://code.sololearn.com/cnOea3y2Dk7c/?ref=app

+ 11

I've found 3 solutions so far... Anyone know how many there are?

+ 11

@Krishna It might be more efficient to go from 1000000000 to 5000000000? Because multiplying over the latter limit would cause resultant integer to exceed 10 digit. This will save you 5000000000 iterations.

+ 11

Yes Sir 😃😃😃

+ 10

Sorry @Hatsy Rei,
palindrome is not reversed.
the first digit and the last digit of the number must be different.
lets see who first @Hatsy or @Krishna Sir
or the other genius here on Sololearn.

+ 10

@Agus Mei How many solutions are there?

+ 10

@Jafca
I found three.
and i can't reach my laptop too now.
if any body has find the answer, post it so i can mark as best answer.

+ 10

just for note i can't check your code now because codeplayground show memory limit.
maybe later at night if i can reach my laptop.

+ 10

@Erangga
nice try
i think you miss the rule.
palindrome is not reversed, it is the same from left and right. anyway multiply by 1 making the answer is identical to the original number.
what i mean is like @Jafca answer.
i hope you understand.

+ 10

Wow you found six possibilities !
oh my God. How genius are you Sir.
I am so happy to find that number.
Thank you very much @Krishna Sir.
😄😄😄😄😄😄😄😄😄😄😄😄😄😄😄
but i am sorry i can't give you best answer because it will againt the rule that is
the faster will get the best answer tick
But you are (no doubt) the winner here.
Thank you again @Krishna Sir.
😄😄😄😄😄😄😄😄😄😄😄😄😄😄😄

+ 10

@Utkarsh
i am planning to upgrade my code into Cashier 2.0
i am not delete it.
just remove it to my laptop, since input in Code Playground often confused beginner.
i'll try to break my math solver in laptop into smaller ones. then i'll post them here.
but i am busy these weeks.(Exam weeks)
maybe june.

+ 9

@Nikhil how did u get this answer?

+ 9

@Nikhil
nice try
but how can your answer reversed?
you break the rule of math.

+ 9

@Agus : No worries about marking as best answer. Our target is to get the correct answer. And, we got it. Keep these puzzles coming!

+ 9

Present Sir

+ 8

1234567890*1=0987654321