Question

The sum of the digits of a two-digit number is 12. If the digits are reversed, the number is decreased by 18. What is the original number?

Answer 1

75, right?

Answer 2

I'm not sure.....I can't do it......

Answer 3

your number XY.
x+y = 12
(10x+y) -(10y+x) = 18
just solve this system

Answer 4

|x and y| <=9

Answer 5

@bmp is right

Answer 6

How do you get that? I'm really screwed up.

Answer 7

your number XY.
x+y = 12
(10x+y) -(10y+x) = 18
just solve this system

Answer 8

the 2 digit number (XY) can be writen like this:
10*x + y = number XY
where x y are decimal notation digits form 0...9

Answer 9

GOT IT

Answer 10

Just think that every base 10 number is of the form
(10^0)*a + (10^1)*b + (10^2)*c... and so on, where 10^0 is the zeroth decimal number, 10^1 is the second etc.
So a two digit number is written as
10^0*y + 10^1*x, or 10x + y, as @myko pointed out.

Answer 11

I understand and I got 75. Thanks!