Quantcast Algebra Tease. The answer is 25 so show me the work please :)? - XP Math - Forums
XP Math Home Sign Up FREE! | Sign In | Classroom Setup | Common Core Alignment PDF Version

Go Back   XP Math - Forums > Welcome > Off-Topic Discussion

Reply
 
Thread Tools Display Modes
Old 07-25-2007   #1
Marc H
Guest
 
Posts: n/a
Default Algebra Tease. The answer is 25 so show me the work please :)?

The sum of the digits of a two digit number is 7. When the digits are reversed, the number is increased by 27. Find the number
  Reply With Quote
Old 07-25-2007   #2
sweet n simple
Guest
 
Posts: n/a
Default

Let digits at tens place is xand at units place is yso no is 10x+yx+y=7.....1stBy reversing the digits, number becomes 10y+xSo10x+y =10y+x -279y-9x=27y-x = 3....2ndsolving both we get2y=10y=5so x = 2so the no is 25.
  Reply With Quote
Old 07-25-2007   #3
Ailane
Guest
 
Posts: n/a
Default

25522+5 = 752-25=27
  Reply With Quote
Old 07-25-2007   #4
ziggle
Guest
 
Posts: n/a
Default

Let a be the first digit and b be the second digit.a+b=710a+b-(10b+a)=27Solving,a+b=79b-9a=2718b =90 =>b=5a=2So, the number is 25.
  Reply With Quote
Old 07-25-2007   #5
Jun Agruda
Guest
 
Posts: n/a
Default

Let x = 1st digit; y = 2nd digit.1st equation:x + y = 7x = 7 - y2nd equation10y + x) - (10x + y) = 2710y + x - 10x - y = 27-9x = 27 - 9yx = -3 + y3rd equation (pair off the value of x in 1st & 2nd equations to arrive at y, the 2nd digit):7 - y = - 3 + y10 = 2y5 = y7 - 5 = x2 = xAnswer:1st digit is x or 2; 2nd digit is y or 5.
  Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 03:51 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2020, vBulletin Solutions Inc.
XP Math