The West Zone Mathematics Competition consists of 40 multiple-choice questions. 5 marks is awarded for a correct answer while 1 mark is deducted for a wrong answer. No marks are awarded or deducted for questions not attempted. A student skipped 6 questions. and scored at least 100 marks. Find the maximum number of wrong answers he gave.

Question

anonymous · Answer

ok so he skipped 6 questions. They won't affect his score in any way so we can just throw them away.
Now you have 34 questions to play with.
he got some of these wrong and the rest of them right and his net score is a 100, right?
let 'x' be the number of questions he got wrong. Since he must've got the rest of 'em right, the number of right answers in (34-x).

Now, let's count his score, shall we?
for every answer he gets right, he gets 4 points.
that means that he gains (34-x)*4 points for his right answers.
and he loses 1 point for every wrong answer i.e. he loses x points in total

so, his total score = 100 =4(34-x) - x.
Solve that and you get x, which is the number of wrong answers.

anonymous · Answer

Wow brilliant way of solving i understand it clearly.

anonymous · Answer

I try :)