The sum of two numbers is three times their difference. What is the ratio of the two numbers?

The ratio of the number of boys and girls in a school of $720$ students is $7: 5$. How many more girls should be admitted to make the ratio $1: 1$?

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?

$A$ man divides his property such that his son's share to his wife's share and his wife's share to his daughter's share are both in the ratio $3:1$. If the daughter gets ₹ $10,000$ less than the son,what is the total value of the property in ₹?

If $a:b = \frac{2}{9} : \frac{1}{3}$,$b:c = \frac{2}{7} : \frac{5}{14}$,and $d:c = \frac{7}{10} : \frac{3}{5}$,then find $a:b:c:d$.

If $P: Q = 8: 15$,$Q: R = 5: 8$,and $R: S = 4: 5$,then $P: S$ is equal to