Concept: The question tests on the ability to solve Word problem

Solution:

Let the number of correct answers = x and number of wrong answers = y

x + y = 90

5x - 2y = 387

Putting x = 90 - y from (1) into equation (2), we get 5(90 - y) - 2y = 387

450 - 5y - 2y = 387

7y = 63

y = 9


 Option A