A test consists of True' or 'False' questions. One mark is awarded for every correct answer while 4
mark is deducted for every wrong answer. A student knew answers to some of the questions.
Rest of the questions he attempted by cheating. He answered 120 questions and got 90 marks. It
answer to all questions he attempted by cheating were wrong, then how many questions did he
answer correctly? How the habit of cheating will affect his character building?
Answers
Answer:
The Calculation for this question is as follows;
Let the number of questions answered correctly be x
And the number of questions answered incorrectly be y
Total number of questions:
= total number of correct answers + total number of incorrect answers = 120 questions
That means, x + y = 120 .....first equation
Marks scored;
For correct answers is 1 mark × x answers = X marks
For incorrect answers -1/2 mark × y answers = -0.5Y marks
Therefore, x +(- 0.5y) = 90 marks
= x - 0.5y = 90 (second equation)
We now have two equations and can thus solve the problem:
x + y = 120 (x = 120-y)
x - 0.5y = 90
Substitute x = 120 - y in the second equation
120 -y - 0.5y = 90
-1.5y = 90 -120
-1.5y = - 30
1.5y = 30
y = 20
...find x
x = 120 - y
x = 120 - 20
x= 100
x is the number of correctly answered questions
Therefore the number correctly answered questions = 100 questions
Dear friend
A test consists of True' or 'False' questions. One mark is awarded for every correct answer while 4
mark is deducted for every wrong answer. A student knew answers to some of the questions.
Rest of the questions he attempted by cheating. He answered 120 questions and got 90 marks. It
answer to all questions he attempted by cheating were wrong, then how many questions did he
answer correctly? How the habit of cheating will affect his character building?