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?

There is $1000 \, \text{litres}$ of milk in a pot. $100 \, \text{litres}$ of milk is taken out and the same amount of water is poured into it. Again, $200 \, \text{litres}$ of the mixture is taken out and the same amount of water is poured into it, and finally, $400 \, \text{litres}$ of the mixture is taken out and the same amount of water is poured into it. What is the amount of milk in the resulting mixture?

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

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

One year ago,the ratio between Ram's and Shyam's salaries was $3:5$. The ratios of their individual salaries of last year to the present year are $2:3$ and $4:5$ respectively. If their total salary for the present year is $Rs. 8600$,find the present salary of Ram (in $Rs.$)?

Two numbers are in the ratio of $5: 8$. If $12$ is added to each,they are in the ratio of $3: 4$. Find the sum of the two numbers.