At present,Kavita is twice Sarita's age. $8 \ yr$ hence,the respective ratio between Kavita's and Sarita's ages will be $22:13$. What is Kavita's present age (in $yr$)?

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

In a mixture of $60 \ L$,the ratio of milk and water is $2:1$. What quantity of water (in $L$) should be added so that the ratio becomes $1:3$?

Ram got twice as many marks in English as in Science. His total marks in English,Science,and Mathematics are $180$. If the ratio of his marks in English and Mathematics is $2:3$,what are his marks in Science?

$A$ man spends $Rs. 2310$ on an average during the first $8$ months from his income. During the next $4$ months,he spends $Rs. 1800$ on an average from his income,but he had taken a loan of $Rs. 1680$ apart from his income to meet his expenses. If he spent all that he had,what is the ratio of his average income to his average expenditure?

If $A : B = 2 : 3$,$B : C = 4 : 5$ and $C : D = 5 : 9$,then $A : D$ is equal to