A candidate who gets 20% marks in a examination fails by 30 marks but another candidate who gets 32% gets 42 marks more than the pass marks. Then the percentage of pass marks is :

Let the maximum marks = x
According to the question,
Case (i) pass marks = $$\frac{20x}{100}$$ + 30
Case (ii) pass marks = $$\frac{32x}{100}$$ - 42
Note : Pass marks would be same in both cases.
$$\frac{20x}{100}$$ + 30 = $$\frac{32x}{100}$$ - 42
$$\frac{12x}{100}$$ = 72
x = 600
Pass marks :
= 600 × $$\frac{20}{100}$$ + 30
= 150
Required percentage :
= $$\frac{150}{600}$$ × 100
= 25%