12. a) In a quiz contest, the quiz master announced the following rules. (+10) marks is awarded for each correct answers. (-5) marks is given as penalty to each incorrect answers. 0 mark is given for not supplying any answers. (i) If the group-A, answered 6 questions correctly and 4 question incorrectly, how many marks did the group-A secure? (ii) If the group-B answered 7 questions correctly, 2 questions incorrectly and did not answer for 1 question, how many marks did the group-B secure? (iii) Which group secured more marks and by how many?
