One year ago,the ratio of Ramu's and Somu's ages was $6:7$ respectively. Four years hence,their ratio will become $7:8$. How old (in years) is Somu?

$A$ certain amount was to be distributed among $A$,$B$,and $C$ in the ratio $2:3:4$,but was erroneously distributed in the ratio $7:2:5$. As a result of this,$B$ received ₹ $40$ less. What is the actual amount (in ₹)?

What is the fourth proportional to $189, 273$ and $153$?

If $\left(x+\frac{1}{x}\right):\left(x-\frac{1}{x}\right)=5:5$,then the value$(s)$ of $x$ is/are:

The ratio between the present ages of $P$ and $Q$ is $5:7$ respectively. If the difference between $Q$'s present age and $P$'s age after $6$ years is $2$,what is the total of $P$'s and $Q$'s present ages (in years)?

On the entire Earth,the ratio between land and water is $1:2$,and in the Northern Hemisphere,this ratio is $2:3$. What will be the ratio of land to water in the Southern Hemisphere?