All about flooble | fun stuff | Get a free chatterbox | Free JavaScript | Avatars    
perplexus dot info

Home > Numbers
Given one, get the other three (Posted on 2017-12-18) Difficulty: 1 of 5
A 2-digit number, divisible by 11, is multiplied by 99.

If the 3rd digit is 7, what is the 4-digit product?

No Solution Yet Submitted by Ady TZIDON    
Rating: 3.0000 (1 votes)

Comments: ( Back to comment list | You must be logged in to post comments.)
Solution Analytical solution Comment 2 of 2 |
Multiplying by 99 is the same as multiplying by 100 and then subtracting the original number.  

If the original number is kk, then after multiplying by 99 the product equals

  -  kk

This is a 4 digit number, whose digits (in order) are

  k, k-1, 9-k, and 10-k

If 9-k = 7 then k = 2 and the digits are 2,1,7 and 8.

Funal answer: 2178

  Posted by Steve Herman on 2017-12-19 09:05:56
Please log in:
Remember me:
Sign up! | Forgot password

Search body:
Forums (0)
Newest Problems
Random Problem
FAQ | About This Site
Site Statistics
New Comments (1)
Unsolved Problems
Top Rated Problems
This month's top
Most Commented On

Copyright © 2002 - 2019 by Animus Pactum Consulting. All rights reserved. Privacy Information