If $P: Q = 8: 15$ and $Q: R = 3: 2$,then find $P: Q: R$.

Present ages of Sameer and Anand are in the ratio of $5 : 4$ respectively. Three years hence,the ratio of their ages will become $11 : 9$ respectively. What is Anand's present age in years?

$A$ milkman makes $20\%$ profit by selling milk mixed with water at $Rs. 9$ per litre. If the cost price of $1 \text{ L}$ pure milk is $Rs. 10$,then the ratio of milk and water in the given mixture is:

$A$ mixture contains alcohol and water in the ratio $4:3$. If $5 \text{ liters}$ of water is added to the mixture,the ratio becomes $4:5$. Find the quantity of alcohol in the given mixture (in $\text{L}$).

If an alloy contains copper and silver in the ratio $3:7$,then the percentage quantity of silver in the alloy is

The students in three classes are in the ratio $4:6:9$. If $12$ students are increased in each class,the ratio changes to $7:9:12$. Then the total number of students in the three classes before the increase is