Answer:
Yes it is possible
Step-by-step explanation:
Given
[tex]n = 20[/tex]
[tex]x= 7[/tex] --- correct
[tex]y = -4[/tex] --- wrong
[tex]z = 0[/tex] --- empty answer
Required
Is a total of -11 possible?
To do this, we apply trial by error method.
After so many approaches, I found the following solution
[tex]x \to 3[/tex] -- Got 3 correctly
[tex]y \to 8[/tex] --- Failed 8
[tex]z \to 9[/tex] ---- Didn't answer 9
The above will give a score of -11.
We have:
[tex]3x+8y+9z[/tex]
[tex]3x+8y+9z = 3 * 7 + 8 * -4 + 9 * 0[/tex]
[tex]3x+8y+9z = 21-32 + 0[/tex]
[tex]3x+8y+9z = -11[/tex]
Hence, a score of -11 is possible