Respuesta :
Given data:
The points obtained after getting correct answer is c=150.
The points losses after getting incorrect answer is i=250.
The expression for total questions is,
[tex]\begin{gathered} c+i=20 \\ i=20-c \end{gathered}[/tex]The expression for total marks is,
[tex]150c-250i=200[/tex]Substitute (20-c) for i in the above expression.
[tex]\begin{gathered} 150c-250(20-c)=200 \\ 150c-5000+250c=200 \\ 400c=5200 \\ c=13 \end{gathered}[/tex]The numbers of incorrect questions are,
[tex]\begin{gathered} i=20-13 \\ =7 \end{gathered}[/tex]Thus, the numbers of correct questions are 13, and numbers of incorrect questions are 7.
