The present ages of Reena and Usha are $24$ and $36$ years,respectively. What was the ratio between the ages of Usha and Reena $8$ years ago?

Hitesh is $40$ years old and Ronnie is $60$ years old. How many years ago was the ratio of their ages $3:5$?

$A$ and $B$ together have ₹ $6300$. If $\frac{5}{19}$ of $A$'s amount is equal to $\frac{2}{5}$ of $B$'s amount,then the amount of $B$ is (in ₹):

In a mixture of petrol and kerosene,the quantity of petrol is $99 \text{ litres}$. If this same quantity of petrol were present in another mixture of petrol and kerosene where the total volume is $198 \text{ litres}$ less than the actual mixture,the concentration of petrol in the actual mixture would be $13.33 \%$ less than that of the new mixture. What is the concentration (in $\%$) of petrol in the actual mixture?

Find two numbers such that their mean proportion is $10$ and their third proportion is $1024$.

The ratio of wine and water in a drum is $3:1$. What part of the mixture is taken out and replaced with an equal amount of water so that the ratio of wine and water in the mixture becomes $1:1$?