 Hello and welcome to the session. In this session we discuss the following question which says a number is increased by 30% and the increased number is decreased by 30% find the net increase or decrease percent. Before moving on to the solution let's recall the formula for decrease percent this is equal to increase upon original value into 100% and the formula for decrease percent is equal to decrease upon original value into 100%. This is the key idea for this question. Let's move on to the solution now. First of all we will assume that let the number be equal to 100. Now the increase percent in the number is equal to 30% as given in the question that a number is increased by 30%. So now let's find out the increase in the number. Now using this formula in the key idea that increase percent is equal to increase upon original value into 100% we can easily find out that increase is equal to increase percent into into original value this total upon 100. So increase is equal to increase percent in the number that is 30 into the original value which is 100 upon 100. So this 100 100 cancels this is equal to 30 that we get increase in the number is equal to 30. So now the increase number is equal to the original number which is 100 plus increase in the number that is 30 equal to 130. As in the question it's given that the increase number is decreased by 30%. So next we have decrease percent in the increase number is equal to 30%. So now we will find out decrease in the increase number is equal to decrease percent into original value upon 100 that is this is equal to 30 into original value in this case would be the increase number that is 130 upon 100. This zero cancels with this zero this zero cancels with this zero and this is equal to 3 into 13 equal to 39. So the decrease in the increase number is equal to 39. So next we have the new number would be equal to the increase number which is 130 minus the decrease in the increase number that is 39. So 130 minus 39 is equal to 91 this is the new number. So our original number was 100 and the new number is now 91. So obviously there is a decrease hence the net decrease is equal to 100 minus 91 and that is equal to 9. Then net decrease percent is equal to the net decrease that is 9 upon the original value that is 100 into 100 percent 100 cancels with 100 and this is equal to 9%. This is the net decrease percent. So final answer is 9%. This completes the session hope you have understood the solution for this question.