Delhi Police Constable Exam Model Paper 4

Tips & Tricks
GIVEN:2 successive discounts of 25% and 40%
CALCULATION:
Single effective discount = [1−(1−0.25)×(1−0.4)]×100
⇒ [1−0.75×0.6]×100
⇒ [1−0.45]×100
⇒ 0.55×100
⇒ 55%
∴ Single effective discount is 55%
Smart Trick
Effective discount for a% and b% discounts = (a + b - ab/100)
So,
Effective discount for 25% and 40% discounts = 25+40−

1000

100

=55%