By what fraction selling price $(S.P.)$ must be multiplied to get the cost price $(C.P.)$ if the loss is $20 \%$?

Mahesh purchased $25\, kg$ of rice at $Rs. 32$ per $kg$ and $15\, kg$ of rice at $Rs. 36$ per $kg.$ He mixed the two varieties of rice and sold it at $Rs. 40.20$ per $kg.$ What is the percent profit earned (in $\%$)?

$A$ man bought apples at the rate of $8$ for $Rs. 34$ and sold them at the rate of $12$ for $Rs. 57$. How many apples should be sold to earn a net profit of $Rs. 45$?

$A$ cycle dealer offers a discount of $10 \%$ and still makes a profit of $26 \%$. What does he pay for a cycle whose marked price is $₹ 840$? (in $₹$)

$A$ sells an article to $B$ for $₹ 45,000$ losing $10 \%$ in the transaction. $B$ sells it to $C$ at a price which would have given a profit of $10 \%$ to $A$. By what per cent does $B$ gain?

$A$ bakery bakes cakes with the expectation that it will earn a profit of $40 \%$ by selling each cake at the marked price. During delivery to the showroom, $16 \%$ of the cakes were completely damaged and could not be sold. $24 \%$ of the cakes were slightly damaged and were sold at $80 \%$ of the cost price. The remaining $60 \%$ of the cakes were sold at the marked price. What is the percentage profit on the whole consignment (in $\%$)?