Asked by Jannie
In a test there were 25 multiple-choice questions. They were marked as follows:
2 marks for each correct answer
0 marks for a non-attempt
1 mark for an incorrect answer.
Sarah attempted
4
5 of the questions and received 22 marks. How many questions did
she answer correctly?
2 marks for each correct answer
0 marks for a non-attempt
1 mark for an incorrect answer.
Sarah attempted
4
5 of the questions and received 22 marks. How many questions did
she answer correctly?
Answers
Answered by
Dr Russ
Again we can set this up as two simultaneous equations
2 marks for each correct answer A
0 marks for a non-attempt (not interested in these)
1 mark for an incorrect answer B
A+B=20 (she only answered 4/5 of 25 questions)
2A+B=22 based on the marks
solve the two for A
2 marks for each correct answer A
0 marks for a non-attempt (not interested in these)
1 mark for an incorrect answer B
A+B=20 (she only answered 4/5 of 25 questions)
2A+B=22 based on the marks
solve the two for A
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