If $x: y = 2: 1,$ then $(x^{2} - y^{2}) : (x^{2} + y^{2})$ is

The ratio between the present ages of Indira and Lizzy is $3:8$,respectively. After $8 \text{ yr}$,Indira's age will be $20 \text{ yr}$. What was Lizzy's age $5 \text{ yr}$ ago (in $\text{yr}$)?

Annual income of Amit and Veer are in the ratio $3:2$,while the ratio of their expenditures is $5:3$. If at the end of the year each saves ₹ $1,000$,the annual income of Amit is (in ₹):

The ratio between the present ages of $A$ and $B$ is $5:3$ respectively. The ratio between $A$'s age $4$ years ago and $B$'s age $4$ years hence is $1:1$. What is the ratio between $A$'s age $4$ years hence and $B$'s age $4$ years ago?

Three numbers $A, B$ and $C$ are in the ratio $12: 15: 25$. If the sum of these numbers is $364$,find the ratio between the difference of $B$ and $A$ and the difference of $C$ and $B$.

The flight fare between two cities is increased in the ratio $9:11$. What is the increase (in ₹) in the fare,if the original fare was ₹ $18,000$?