Question

Mohan gets $3$ marks for each correct sum and loses $2$ marks for each wrong sum. He attempts $30$ sums and obtains $40$ marks. The number of sums solved correctly is

• A. $10$
• B. $15$
• C. $20$
• D. $25$

Answer 1

The correct option is C $20$

It is given that, Mohan gets $3$ marks for each correct answer and loses $2$ marks for each wrong answer.

He attempted $30$ sums and got $40$ marks.

Let the number of sums solved correctly be $n$.
Then number of wrong sums $=30-n$
$\therefore 3n-2.(30-n)=40$

$\Rightarrow 3n-60+2n=40$

$\Rightarrow 5n=100$
$\Rightarrow n=20$