Abhinav save Rs. 25 by getting 6.66% discount on a textbook.What is the amount of money (in Rs.) paid by him?

He sells 95 litre petrol at the price of 100 litre.
So profit % = [ 5 / 95 ] X 100 = 5.26%

Its simple i.e. 25% nothing else, which is very obvious

Loss % = ( common gain or loss / 10 )² %
= (20 / 10)² %
= 4%

Now assume total CP of both articles be x, then SP = 0.96x = 400
x = 400 / 0.96 = CP

loss = 4% of CP
= (4 / 100) X (400 / 0.96) = Rs. 16.66

Loss % = ( common gain or loss / 10 )² %
= (20 / 10)² %
= 4%

CP / SP = 29x / 19x
loss % = 29x - 19x / 29x X 100 = 34.48 %

(To understand the concept assume CP of each article Rs 29 and SP of each article = Rs. 19)

Abhishek Discount = 2800
Bhanu Discount =2400+640=3040

The difference in selling price is same as difference in discount = 3040 - 2800 = Rs.240

From the question
10 % x = 15% of y ...(i)
x+y = 30000 ...(ii)

from eq. (i)
x / y = 3/2 ...(iii)

by solving eq. (ii) & (iii)
x = 18000, y = 12000

Hence, the difference =6000

Let the cost price of 1 litre pure milk be Rs. 1, then
for 6 litres (milk) CP = Rs. 6
for 2 litres (Water) CP = Rs. 0

and for 8 litres mixture SP = 8 x 2 = Rs.16

Profit = [(16-6) / 6] x 100 = 1000 / 6 = 166.66 %

Initially :
CP =100
SP = 140 (Since profit = 40 %)

New price :
CP =100
SP = 140 - 20% = 112
MP = 140

Profit % = [(112 - 100 )/100] = 12 %

CP : MP = 2y : 3y
profit = y
(%) profit : (%) discount =3 : 2

Let CP=200, SP=300
So [ (3y / 100) x 200 ] + [(2y/100) x 300] = 100
y= 8.33 %
Discount 2y = 16.66 %