anjaneiya wrote:Q1:
A test has 50 questions. A student scores 1 mark for a correct answer, -1/3 for a wrong
answer, and -1/6 for not attempting a question. If the net score of a student is 32, the number
of questions answered wrongly by that student cannot be less than
1. 6 2. 12 3. 3 4. 9

pl explain . thanks.

Say, the number of correct answers = x, number of wrong answers = y and number of questions not attempted = z.
Thus, (x + y + z) = 50 and (x - y/3 - z/6) = 32

The second equation can be written as, (6x - 2y - z = 192)

Adding the two equations we get, (7x - y) = 242 => x = (242 + y)/7

Since, x and y are both integers, (242 + y) must be divisible by 7 for integer values of y.
The minimum value that y can have is 3.

The correct answer is C.