Question

In a class test $(+3)$ marks are given for every correct answer and $(-2)$ marks are given for every incorrect answer and no marks for not attempting any question. Radhika scored $20$ marks. If she has got $12$ correct answers, how many questions has she attempted incorrectly?

Answer 1

Find the required value.

It is given that Radhika has got $12$ correct answers.

Radhika marks for correct answers can be given by $12\times 3=36$.

Assume that, Radhika has got $x$ incorrect answers.

So, according to the question.

$$\begin{gathered} 36-2\mathrm{x}=20 \\ \Rightarrow -2\mathrm{x}=-16 \\ \Rightarrow \mathrm{x}=8 \end{gathered}$$

Therefore, Radhika has got $8$ incorrect answers.

Hence, Radhika attempted $8$ questions incorrectly.