Question

In a test, $+3$ marks are given for every correct answer and $-1$ mark are given for every incorrect answer. Sona attempted all the questions and scored+20 marks though she got 10 correct answers.
i. How many incorrect answers has she attempted?
ii. How many questions were given in the test?

Answer 1

$\left(i\right)$ The total correct answer given by Sona was $10$ but she obtained $20$ marks.

$\because$ $1$ correct answer of $3$ marks then

Marks cut for the incorrect answer $=20-10\times 3=20-30=-10$

From question, $-1$ mark is given for every incorrect answer.

Hence, total incorrect answers $=\frac{-10}{-1}=10$

$\left(ii\right)$ Total correct answer given $=10$

Ans from part $\left(i\right)$ we know that,

Total incorrect answer given $=10$

Therefore, the total question asked in the test (examination)$=10+10=20$