A dairyman pays $Rs.\, 6.40$ per litre of milk. He adds water and sells the mixture at $Rs.\, 8$ per litre, thereby making $37.5\%$ profit. The proportion of water to milk received by the customers is
$1: 10$
$1: 12$
$1:15$
$1:20$
A shopkeeper cheats to the extent of $10 \%$ while buying as well as selling, by using false weights. His total gain is in $\%$
The marked price of a watch was $Rs.\,720.$ A man bought the same for $Rs.\, 550.80$ after getting two successive discounts, the first being $10 \% .$ The second discount rate is.......$\%$
A shopkeeper sold some articles at $Rs.\,35$ per piece and gained $40 \% .$ What would be the selling price of each article to earn $60 \%$ profit? (in $Rs.$)
A shopkeeper gains $17 \%$ after allowing a discount of $10 \%$ on the marked price of an article. Find his profit percent if the article is sold at marked price allowing no discount.
A sells an article to $B$ at a gain of $20 \%$ and $B$ sells it to $C$ at a gain of $10 \%$ and $C$ sells it to $D$ at a gain of $12 \frac{1}{2} \% .$ If $D$ pays $Rs.\, 29.70,$ then $A$ purchased the article for (in $Rs.$)