SOLUTION: at an entrance exam the students score 1 mark for every right answer and losses 0.25 mark for every wrong answer. if a question is left unanswered no marks is deducted. To gain adm

Algebra ->  Coordinate Systems and Linear Equations  -> Linear Equations and Systems Word Problems -> SOLUTION: at an entrance exam the students score 1 mark for every right answer and losses 0.25 mark for every wrong answer. if a question is left unanswered no marks is deducted. To gain adm      Log On


   

Question 1072018: at an entrance exam the students score 1 mark for every right answer and losses 0.25 mark for every wrong answer. if a question is left unanswered no marks is deducted. To gain admission a student has to scored 60 or above. A student X left some questions unanswered in the test after the test he realised that to gain admission not more than 20 of his answered question should be wrong. he also realised that had he attempted the entire question paper and had a maximum of 28 questions been wrong he still would have got the admission. how many question did he leave the answer?
Answer by KMST(5328) About Me  (Show Source):
You can put this solution on YOUR website!
N= number of questions in the whole test
x= number of questions the student did not attempt
N-x= number of questions the student answered.
If he had answered 28 wrong and N-28 right,
his score would have been
%28N-28%29-0.25%2A28=60
You can solve that for N many ways.
For example
N-1.25%2A28=60
N-35=60
N=60%2B35
N=95
The student knows that if 20 of his answers were wrong,
his scores would be
N-x-20-0.25%2A20=60
95-x-20-5=60
70-x=60
70-60=x
x=10
So the strident left out the answer for 10 questions.
He only answered the other 95-10=85 questions.