Question

by selling 125 CDs , a man gains an amount equal to the selling price of 5 CDs . find the gain percent

Answer 1

Let the selling price of each cassette=Rs.
Selling price of 125 cassettes=Rs.125xProfit

gained=Rs.5xCP=SP-ProfitCP=120xProfit%=(profit/CP)
*100Profit%=(5x/120x)
*100Profit=4.150~4%
Hope it helps.

Answer 2

let the sp of each CD=Rs.x
sp of 125 CDs - sp of 5 CDs=CP= Rs.125x -Rs.5x=Rs.120x
Gain%= (gain/cp)×100=(5x/120x)×100=4.15%