Kathy's age problem

If three times Kathy's age is decreased by 36, the result is twice Kathy's age. How old is Kathy?

x = Kathy's age 

3x - 36 = 2x   {three times her age minus 36 equals twice her age}
-36 = -x  {subtracted 3x from both sides}
x = 36   {divided both sides by -1} 

Kathy is 36


- Algebra House