Question

Abdallah noticed that if he takes the opposite of his age and adds 40, he gets the number 28.

Ali wants to know Abdallah's age. He wrote the equation -x + 40 = 28 And he got his age as 68.

What was Ali's mistake? how old is Abdallah?

Please solve neatly and show steps.

Answer 1

The equation is correct. He did mistake is calculation. The correct calculation is:

-x + 40 = 28

=> 40 = 28 + x

=> 40 - 28 = x

=> 12 = x