Problem Solving

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

6
12
3
9
15

answer (c) 3

sanjayism wrote:answer (c) 3

sanjayism will you provide detailed solution of the same though its a simple question of conditinal 3 unknowns....BTW you are correct in your answer it is C ie. 3.

no of correct answers ( a) mark +1
no of incorrect answers ( b) mark -1/3
no of un-attested answers ( c) mark -1/6

a+b+c =50 (i.e. total no of questions) -------------------------------------(i)

1*a + (-1/3)*b + (-1/6) * c = 32 ( i.e. total marks obtained) ----------(ii)

(i)+(ii)*6

7 * a - b =242

a= (242+b)/7
= 34 +[(b+4)/7]

b=3 is only value from the answer choice which give an integer value of a . no of correct answered question must be integer.