On selling a tea set at 5% loss and a lemon set at 15% gain, a shopkeeper gains Rs. 70. If he sells the tea set at 5% gain and lemon set at 10% gain, he gains Rs. 130. Find the cost price of the lemon set.
Let C.P of tea set =x and lemon set =y
ATP, 15100×y−5100×x=70⇒3y−x=70×20⇒3y−x=1400⟶(1)
Again,
5100×x+10100×y=130⇒x+2y=130×20⇒x+2y=2600⟶(2)
Substituting x from equation (1) in equation (2)
3y−1400+2y=2600⇒5y=4000⇒y=800