The difference between the ages of Meena and Seema is $3 \ yr$ and the ratio between their ages is $7: 8$. What is the sum of their ages (in $yr$)?

In a mixture of $60 \, \text{litres}$,the ratio of milk and water is $2:1$. What amount of water (in $\text{litres}$) must be added to make the ratio of milk and water $1:2$?

If $A : B = 7 : 9$ and $B : C = 8 : 11,$ find $A : B : C$.

The ratio of students in school $A, B$ and $C$ is $5: 4: 7$ respectively. If the number of students in schools are increased by $20\%$,$25\%$ and $20\%$ respectively,then what will be the new ratio of students in school $A, B$ and $C$?

$x$ varies inversely as the square of $y$. Given that $y = 2$ when $x = 1$. The value of $x$ when $y = 6$ will be equal to:

$A$ sum of ₹ $1,300$ is divided amongst $P, Q, R$ and $S$ such that $\frac{P \text{'s share}}{Q \text{'s share}} = \frac{Q \text{'s share}}{R \text{'s share}} = \frac{R \text{'s share}}{S \text{'s share}} = \frac{2}{3}$. Then $P$'s share is (in ₹):