Explanation:
Let x represent the number of correct answers School A gave.
Then x is also the number of incorrect answers School A gave and the number of correct answers School B gave.
Final score of School A
= 165 + 12x - 5x.
Final score of School B
= 65 + 12x
Hence the correct equation is
12x - 5x + 165 = 12x + 65. (B)
=> 7x + 165 = 12x + 65
=> 5x = 100
=> x = 20
Hence Schools A and B got 20 correct answers each.