Question

An online exam has 100 questions. A candidate gets 3 points for every correct answer, and -9 for every wrong answer, and questions cannot be skipped. How many correct answers must a candidate have to score 240

Answer 1

Friend,
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Question: 

An online exam has 100 questions. A candidate gets 3 points for every correct answer, and -9 for every wrong answer, and questions cannot be skipped. How many correct answers must a candidate have to score 240

Solution 

Lets consider the no of correct ans given by the students to be x.

Lets consider the no of incorrect ans given by the students to be y. 

So from the above data we can make two equations.

The first data says that 


A candidate gets 3 points for every correct answer, and -9 for every wrong answer, and questions cannot be skipped. and he scored 240 

So the equation for this data becomes 

3x - 9y = 240                  --------- 1 

x  -3y  = 80                    ----------- 2

Second data says that 

An online exam has 100 questions.

So the equation for it becomes

x + y = 100                                                ------3

x =100-y                                                  --------4


So now solving equations 

Substitute 3 in 2

That is

100 - y - 3y = 80

4y = 20

y = 5 

so x = 95 

So the number of correct ans given by the student is 95.

the number of incorrect ans given by the student is 5.

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 hope this helps

regards

Answer 2

Answer:

Your answer in the attachment