 Hello and welcome to the session. In this session we discussed the following question which says, the salary of an officer is increased by 30% by what percentage should the new salary be reduced to restore the original salary. First let's recall the formula for increase percent and decrease percent. We have increase percent is equal to increase upon original value into 100% Then decrease percent is equal to decrease upon original value into 100%. This is the key idea to be used in this question. Let's move on to the solution now. First we assume that the original salary be equal to rupees 100. Then increase in the salary is given as 30%. That is we are given the increase percent. Now using this formula for increase percent we can find out the increase and this would be equal to increase percent that is 30 into the original salary that is 100 upon 100. So we would get this equal to rupees 30. That is the increase in the salary is rupees 30. So now salary after increase is equal to the original salary rupees 100 plus the increase in the salary rupees 30. That is equal to rupees 130. Now we need to find out that by what percentage should the new salary be reduced to restore the original salary. So to restore the original salary the reduction required would be equal to the salary after increase that is rupees 130 minus the original salary which is rupees 100. And so this is equal to rupees 30. So to restore the original salary reduction is equal to rupees 30. Now let's find out the reduction percent. This is equal to using this formula for decrease percent that is equal to decrease upon original value into 100%. So reduction percent is equal to reduction that is 30 upon the original value which is the salary after increase that is 130 into 100%. This zero cancels with this zero and so this is equal to 300 upon 13% and this is equal to 23.08% is the reduction percent. Thus we have the new salary must be reduced by 23.08% to restore the original salary. So this is our final answer 23.08%. So this completes the session hope you have understood the solution for this question.