In an examination out of $900$ students,$85 \%$ of the boys and $70 \%$ of the girls passed. How many girls appeared in the examination,if the total pass percentage was $75 \% ?$

The ratio in which tea costing $Rs. 192$ per $kg$ is to be mixed with tea costing $Rs. 150$ per $kg$ so that the mixed tea,when sold for $Rs. 194.40$ per $kg$,gives a profit of $20\%$,is:

Mira's expenditure and savings are in the ratio $3: 2$. Her income increases by $10 \%$. Her expenditure also increases by $12 \%$. By how many $\%$ does her saving increase?

In two types of brass,the ratios of Copper to Zinc are $8:3$ and $15:7$ respectively. If the two types of brass are melted and mixed in the ratio $5:2$,a new type of brass is obtained. The ratio of Copper to Zinc in this new type of brass is:

How much water should be added to $14$ litres of milk worth ₹ $5.40$ a litre so that the value of the mixture may be ₹ $4.20$ a litre? (in litres)

$60\, kg$ of an alloy $A$ is mixed with $100\, kg$ of alloy $B.$ If alloy $A$ has lead and tin in the ratio $3:2$ and alloy $B$ has tin and copper in the ratio $1:4,$ the amount of tin in the new alloy is (in $kg$)