A candidate who gets 20% marks in an examination, fails by 30 marks. But if he gets 32% marks, he gets 42 marks more then the minimum pass marks. Find the pass percentage of marks.

Let maximum marks in the examination = $$100x$$ and passing marks = $$y$$

Marks secured by candidate = $$\frac{20}{100}\times100x=20x$$

Thus, $$20x=y-30$$ -------------(i)

Similarly, $$32x=y+42$$ -------------(ii)

Subtracting equation (i) from (ii), we get :

=> $$32x-20x=42+30$$

=> $$12x=72$$

=> $$x=\frac{72}{12}=6$$

Substituting it in equation (i), => $$y=20(6)+30=120+30=150$$

$$\therefore$$ Pass % = $$\frac{y}{100x}\times100=\frac{y}{x}$$

= $$\frac{150}{6}=25\%$$

=> Ans - (B)