What will be the duplicate ratio of $2: 7$?

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?

If the income of $A$,$B$,and $C$ is in the ratio of $2: 5: 11$ and the income of $B$ is ₹ $291$ more than that of $A$,then the income of $C$ is (in ₹).

Find the mean proportional between $9$ and $64$.

If $1,000$ copies of a book of $25$ sheets require $50$ reams of paper,how much paper is required for $5,000$ copies of a book of $32$ sheets?

₹ $864$ is divided among $A, B$ and $C$ such that $8$ times $A$'s share is equal to $12$ times $B$'s share and also equal to $6$ times $C$'s share. How much (in ₹) did $B$ get?