Successive discounts of $10 \%$,$20 \%$ and $50 \%$ will be equivalent to a single discount of .......... $\%$

$A$ cloth dealer professes to sell cotton at cost price, but uses a meter scale having a length of $80 \, cm$ only and charges for a full meter. Find his gain percent.

There is a profit of $20 \%$ on the cost price of an article. The per cent of profit, when calculated on the selling price is.......$\%$

Mr. Kapur purchased two toy cycles for $Rs. 750$ each. He sold these cycles,gaining $6 \%$ on one and losing $4 \%$ on the other. The gain or loss percent in the whole transaction is

By selling an article for $Rs. 102$,there is a loss of $15 \%$. When the article is sold for $Rs. 134.40$,the net result in the transaction is:

$A$ shopkeeper cheats to the extent of $10 \%$ while buying as well as selling by using false weights. His total gain percentage is: