Question

in a certain test,+3 marks are given for every incorrect answer. sonal attempted all the questions and scored +20 marks even though she answered only 10 questions correctly? a) how many of her answers were incorrect? b) overall how many questions were given in the test? ​

Answer 1

(i) The total correct answer given by Sona was 10 but she obtained 20 marks.
∵ 1 correct answer of 3 marks then
Marks cut for the incorrect answer =20−10×3=20−30=−10
From question, −1 mark is given for every incorrect answer.
Hence, total incorrect answers =
−1
−10
​
=10

(ii) Total correct answer given =10
Total incorrect answer given =10
Therefore, the total question asked in the test (examination)=10+10=20
Hope it helps.
Thanks.