Tha sum of the digits of a two-digit number is 15. If the digits are reserved the new number is 27 less than the orginal number. Find the original number.
2007-02-05 12:20:19 · 6 answers · asked by surina g 1 in Science & Mathematics ➔ Mathematics
x+y=15
10y+x= 10x+y-27
Two equations, two variables. Solve it!
Done!
2007-02-05 12:23:31 · answer #1 · answered by Jerry P 6 · 1⤊ 0⤋
the number is 96, ... only two sets of digits add up to 15, 6&9, 8&7, the difference between 87 and 78 is 9, and the difference between 96 and 69 is 27
2007-02-05 20:24:31 · answer #2 · answered by cookiemonster 1 · 0⤊ 0⤋
x + y = 15 from first sentence
number xy has value 10x + y
number yx has value 10y + x
10x + y = 10y + x + 27
Use substitution from first equation:
y = 15 - x and substitute
10x + (15 - x) = 10 (15 - x) + x + 27
9x + 15 = 177 - 10x
19x = 162
x = 8, y = 7
2007-02-05 20:27:46 · answer #3 · answered by bozo 4 · 0⤊ 0⤋
yikes....hmmm i would just use variables and then guess and check...i actually don't know what reserved means so sorry i cannot help you there, but try the guess and check method and use like x and y as the numbers... sorry this didn't help too much but maybe it did! who knows! lol GOOD LUCK!
2007-02-05 20:24:19 · answer #4 · answered by soccerqueen155 2 · 0⤊ 1⤋
No, it's not homework....It's just a question that popped into your head!
Start working your x's and y's.
2007-02-05 20:28:18 · answer #5 · answered by poutine 4 · 0⤊ 0⤋
Just use trial and error
2007-02-05 20:23:07 · answer #6 · answered by Aaron 4 · 0⤊ 1⤋