Increase and Decrease Percentage Problem

We had earlier seen successive Discount in previous trick here. If you haven’t gone through it first please go through that and then come here.

Here we will see different problem where both percentage increase and decrease or vice versa is there.

Ques. An online shopping website sells a product for 1000Rs and then gives 40% discount and he then increases price by 50%. What is the final price of the product?

Let initial number be 100.

  • It is quiet obvious that for 100, after giving x% discount the price will be 100 – x. So, (100 – 40) = 60
  • For 60 we do same thing again we calculate 50% increase, which easily can be 5x(10% of 60) = 5x(6) =30
  • So 50 % now is 30, thus after discount price will be 60 + 30 = Rs90.
  • Thus for 1000 -> 90(1000/100) = Rs900 Answer

Now try to Solve the same Question yourself, with 25% increase and 25% decrease.

Note – Please don’t see the solution below until you solve it.

It was quiet obvious to think that answer will be 100 but its not.

  • First we calculate 25% of 100, which will be 25. So new amount is 125.
  • Now we will calculate 25% dec in 125. For which we will do following –
    • Calculate 10% of 125 = 12.5, thus 20% is 2(12.5) = 25
    • Here rather than calculating 1% and multiply by 5 its better to divide 10%/2 to calculate 5%. Thus 6.25 is 5%
    • So total is 25 + 6.25 = 31.25 and value 93.25
    • Now price = 93.25(1000/100) = 932.5Rs.

There is no direct formula for such kind of problems.