Question

XX thinks that is you increase a number by 10% and then decrease it by 10% you are right back where you started.
Prove XX is incorrect by using a specific example?

Answer 1

Let the number be 100
10% of 100 = (10/100)* 100 = 10
So new increased number = 100 + 10 = 110

Now 10% of 110 = (10/100)*110 = 1100/100 = 11

So on subtracting we get 110 - 11 = 99

So we end up with a number which is less than the 100 we started with..