The mean proportional between $64$ and $81$ is

If ₹ $126.50$ is divided among $A, B$ and $C$ in the ratio of $2: 5: 4$,the share of $B$ exceeds that of $A$ by (in ₹) (in $.50$)?

Two numbers are in the ratio $2:3$. If $2$ is subtracted from the first and $2$ is added to the second,the ratio becomes $1:2$. The sum of the numbers is:

The ratio of the number of boys to girls in an institution is $6:5$. If there are $192$ boys in total,find the total number of students in the institution.

If $a-b : b-c : c-d = 1 : 2 : 3$,then what is the value of $(a+d) : c$?

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