(i) Marks given for one correct answer = 3
Marks given for 12 correct answers = 3 x 12 = 36
Radhika scored 20 marks.
Therefore, Marks obtained for incorrect answers = 20 – 36 = –16
Now, marks given for one incorrect answer = –2
Therefore, number of incorrect answers = (-16) ÷ (-2) = 8
Thus, Radhika has attempted 8 incorrect questions.
(ii) Marks given for seven correct answers = 3 x 7 = 21
Mohini scores = –5
Marks obtained for incorrect answers = = –5 – 21 = –26
Now, marks given for one incorrect answer = –2
Therefore, number of incorrect answers =(-26) ÷ (-2) = 13
Thus, Mohini has attempted 13 incorrect questions.







Using laws of exponents, simplify and write the answer in exponential form:
(i) 32 × 34 × 38 (ii) 615 ÷ 610 (iii) a3 × a2 (iv) 7x×72 (v) (52) ÷ 53 (vi) 25 × 55 (vii) a4 × b4 (viii) (34)3(ix) (220 ÷ 215)×23 (x) 8t ÷ 82