Profit/loss problem on goat and sheep same price

If selling price of an item is 5/3 times its cost price, profit/loss is

10% loss on selling price is what percent loss on cost price?

A person bought an article and sold it at a profit of 20%. Had he bought it at 20% less, what would have been the profit percentage if the selling price had been the same?

A profit of 10% is made when a smartphone is sold at P rupees and there is 4% loss when the smartphone is sold at Q rupees. Then P : Q is

The cost price of 20 articles is the same as the selling price of x articles. If the profit is 25%, then the value of x is: