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a test has 12 problems and each problem is worth 5 marks. Full marks are given for a correct answer, 2 marks are given if there is no answer, and no marks given for an incorrect answer. Some scores between 1 and 60, are impossible to get on this test. What is the sum of these impossible-to-get scores

 Feb 25, 2019

Best Answer 

 #2
avatar+99272 
+1

Let x be the number of correct answers,

let y be the number of no answers.

\(x+y\le12\)

 

score = 5x+2y

 

 

Here I have just written the possible scores in a way that is easier to see.

 

 

You can add them together yourself.

 Feb 25, 2019
 #1
avatar
+1

 

I don't have a mathematical proof,

but I think the only impossible-to-get scores are 1 and 3.

If I'm correct, the sum of these impossible-to-get scores would be 4. 

 

.

 Feb 25, 2019
 #2
avatar+99272 
+1
Best Answer

Let x be the number of correct answers,

let y be the number of no answers.

\(x+y\le12\)

 

score = 5x+2y

 

 

Here I have just written the possible scores in a way that is easier to see.

 

 

You can add them together yourself.

Melody Feb 25, 2019
 #3
avatar+98091 
+1

Nice, Melody.....you have laid this out so it's easy to see!!!

 

 

cool cool cool

CPhill  Feb 25, 2019
 #4
avatar+99272 
0

Thanks Chris :)

Melody  Feb 25, 2019

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