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

Find the third proportional to the numbers $4$ and $42$.

The ratio of the number of boys and girls in a school is $3:2$. If $20\%$ of the boys and $25\%$ of the girls are scholarship holders,what percentage of the students does not get the scholarship?

When $30$ percent of one number is subtracted from another number,the second number reduces to its four-fifth. What is the ratio between the first and the second number respectively?

The incomes of $A$ and $B$ are in the ratio $3:2$ and their expenditures are in the ratio $5:3$. If each saves ₹ $1000$,then $A$'s income is (in ₹):

If $\frac{a}{3} = \frac{b}{8}$,then $(a + 3) : (b + 8)$ is equal to