If the answer would be D you had a decrease of 75% and NOT 25%

In these kinds of questions, it is always safe to assume numbers.

Let's say the initial price \(= 100\) & \(z = 20\)

decreasing by \(25\)% so the price \(= 75\)

Now, decreasing the new price by \(z\)%\( = 20\)%

Final price \(= (1 - \frac{20}{100})*75 = 60\)

Now, we have the final price \(= 60\) and in the question, it is asked that \(60\) is equivalent to reducing the initial price by how much? In our case, it will be \(40\)% You can put \(z = 20\) and the answer with \(40\) is correct.

Answer A

I understood the solution but can you please tell me where did I go wrong? So that I don't repeat it.

Sir,

What you did was like you multiplied the discounted prices. This can be seen as a problem with successive discounts.

Let's say if we are given a successive discount of x% & y% for a certain product, the final discount will be \((x + y - \frac{xy}{100})\)% but not \(xy\)%

Sir, I didn't understand this explanation. Please guide.

With your assusmptions only, if the price is 100, and 25% disc is applied, then the new price is 75. The z% disc is applied. So, new price = (1-z/100) * 75

Decreasing the original price of an item by 25%...................is equivalent to decreasing the original price by

It is 0.25. Because you are decreasing by 25% so the decrease is 25. 75 on the other hand is the end result.

By the question is asking you the decreasing. the unit in terms of % when you go from 100 to 75 and this gap is 25%

Let original value be 1


1 x 75/100 x 100-z/100


3/4 (100-z/100)


300 - 3z/400


Amount by which original value decreased


1 - (300- 3z/400)


400 - 300 + 3z/400


100/400 + 3z/400


1/4 + 3z/400


1/4 ( 1 + 3z/100)

0.25( 1 + 3z/100)

Answer A