In a test,2 marks are given for every sum right,and 1 mark is deducted for every sum wrong.if a boy works 9sums and obtains 9 marks ,how many sums were right?
Answers
Answered by
1
Answer:
9
Step-by-step explanation:
You said there were nine sums if that is true and 1 incorrect equals one mark and he got nine marks than there will be 9 incorrect answers leaving 9 marks for nine sums.
Answered by
1
you buy 9 questions and have 9 marks
therefore
9marks = (6 right question)+( 3 wrong )
=( 6×2)+((3×(-1))
=12 -3
=9marks
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