In an examination, a student who gets 20% of the maximum

In an examination, a student who gets 20% of the maximum marks fails by 5 marks. Another student who scores 30% of the maximum marks gets 20 marks more than the pass marks. The necessary percentage required for passing is :

Let the maximum marks be x.
According to question,
20% of x + 5 = 30% of x –20
⇒ (30 –20)% of x = 25

⇒ x =	25 × 100	= 250
	10

∴ Passing marks
= 20% of 250 + 5 = 55
∴ % Passing marks

=	55	× 100 = 22%
	250

Aliter : Using Rule 22,
Here, m = 30%, n = 20%, p = 5 and q = 20
∴ Maximum marks

=	100	× (p + q)
	(n - m)

=	100	× (5 + 20)
	(30 - 20)

=	100 × 25	= 250
	10

Passing marks
= 20% of 250 + 5 = 55
∴ % of passing marks

=	55	× 100 = 22%
	250