The sum of the digits of a certain two digit nuber is 12. when you reverse its digits you increase the number by 18.find the number
two digit number AB ==> 10A + B
A + B = 12 . (1)
(10A + B) - (10B + A) = 18 ---> 11A - 9B = 18 . (2)
Solve the system.
A = 7
B = 5
The number is 75.