A man sells a TV set for Rs. 6,900 and makes a profit of 15%. He sells a second TV set at a loss of 10%. If on the whole, he neither gains nor loses, find the cost price of the second TV set.
For first TV:
SP=Rs. 6,900
Profit =15%
Now, with this SP,
Profit %=SP−CPCP×100
⇒15=6900−CPCP×100
⇒6,900−CP=0.15CP
⇒1.15CP=6900
⇒CP=Rs. 6000
Let the cost price of the second TV be x and it is given that there is a loss of 10%
So,
Loss %=CP−SPCP×100
⇒10=x−SPx×100
⇒x−SP=0.10x
⇒0.9x=SP…(i)
Given, there is no profit or loss in the whole
transaction that means total sales are equal to the total cost price of TV sets. So,
Total SP= Total CP
⇒6900+0.9x=6000+x [From equation (i)]
⇒6900−6000=x−0.9x
⇒900=0.1x
⇒x=Rs. 9000
Thus, the cost price of the second TV is Rs. 9,000.