By selling an umbrella for Rs.336, a shopkeeper loses 4%. At what price must he sell it to gain 4%?

If the selling price of a flower vase is of its cost price, find the loss per cent.

By selling a bouquet for Rs.322, a florist gains 15%. At what price should he sell it to gain 25%?

A radio is sold for Rs.3120 at a loss of 4%. What will be the gain or loss per cent if it is sold for Rs.3445?

Lwani sold two sarees for Rs.1980 each. On one, she lost 10%, while on the other she gained 10%. Find her gain or loss per cent in the whole transaction.