Discount and Percentage

Quantitative Finance Level 1

Find the single discount which is equivalent to a discount of 20% followed by a 30% discount.

4 solutions

Chew-Seong Cheong
Feb 23, 2015

Let the principal amount be $A$ , discounted amount be $B$ and the final discount be $d$ . Then:

$B = (1-0.2)(1-0.3)A = 0.8 \times 0.7 A = 0.56A = (1-0.44)A = (1-d)A$

$\Rightarrow d = 0.44 = \boxed{44}\%$

44 is not the correct answer, 44% is the correct answer, units matter people.

Michael Barnes - 5 years, 5 months ago

Thanks. I did key in % but it didn't show up in LaTex. We need to put a backslash "\" in front of it.

Chew-Seong Cheong - 5 years, 5 months ago

That's what I wanted! You are correct sir!

Sravanth C. - 6 years, 3 months ago

Effective Discount after successive discount of a% and b% is (a + b – a.b/100). In this problem:

Effective discount = (20 + 30 - 20.30/100) % =(50 - 6) % =44%

amit sachdeva - 5 years, 5 months ago

Sravanth C.
Feb 23, 2015

Don't give your answer as 56%...........

Actually there are two methods, I'll give you one(a bit complicated one) you figure out the simpler one...

If D% is the required discount percent then,

D% = [1-(0.8 * 0.7)] * 100 = 44%

which is nothing but 44%...............

this is the easiest one :)

Sushil Kumar - 5 years, 9 months ago

I answer 44% and it said I was wrong.

Michael Barnes - 5 years, 5 months ago

Peter Granato
May 17, 2015

1-.2=.8
.8*.3=.24
.24+.2=.44
44% is the answer

Henry Koffa
Jan 6, 2016

(.8 x .3) + .2 = .24 + .2 = .44 = 44%