13. In a quiz contest, rules are made to provide (+3) for each corres
answer and (-2) for each incorrect answer.
(a) Group A scored 18. if they answered 12 question
incorrectly, find out how many questions they answered con
rectly?
(b) Group B obtained (-5) marks. If they answered 7 questions
were answered incorrectly and find out how many questions
they answered correctly.
(c) Which group answered most of the questions correctly? How
many more questions did the group answer?
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