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

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 sells an article at a gain of $10 \%$. Had he sold it at a loss of $20 \%$,its selling price would have been $Rs. 180$ less. What is the cost price of the article? (in $Rs.$)

On selling an article for $Rs. 500$,the loss incurred is $20 \%$. To make a profit of $20 \%$,the article must be sold at what price in $Rs.$?

$A$ shopkeeper bought $30\, Kg$ of wheat at the rate of $Rs.\, 45$ per $Kg$. He sold $40\%$ of the total quantity at the rate of $Rs.\, 50$ per $Kg$. Approximately,at what price per $Kg$ should he sell the remaining quantity to make $25\%$ overall profit? (in $Rs.$)

There would be a $10 \%$ loss,if rice is sold at $Rs. 54$ per $kg$. To earn a profit of $20 \%$,the price of rice per $kg$ will be (in $Rs.$)