Subtraction/ Score and Percentage. Help me out with this one please.

Hi everyone,

Are the following sentences correct? If not, then please do not hesitate to correct them, please.

  • The teacher subtracted 1 mark for each wrong answer.

  • The teacher subtracted 1 point for each wrong answer.

  • The teacher subtracted 1 mark for a wong answer.

  • The teacher subtracted 1 point for a wrong answer.

  • He scored 95 out of (a) 100 on his English examination.

  • How much per cent of our brains do we use?

Thanks
Alexandro

  • The teacher subtracted 1 mark for each wrong answer.
  • The teacher subtracted 1 point for each wrong answer.
  • The teacher subtracted 1 mark for a wrong answer.
  • The teacher subtracted 1 point for a wrong answer.
  • He scored 95 out of a hundred / one hundred on his English examination.
  • What per cent of our brains do we use?

Thanks MM.