If $A: B = \frac{1}{2}: \frac{3}{8}$,$B: C = \frac{1}{3}: \frac{5}{9}$ and $C: D = \frac{5}{6}: \frac{3}{4}$,then the ratio $A: B: C: D$ is

Find the number which,when subtracted from the terms of the ratio $12: 17$,makes it equal to the ratio $2: 3$.

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?

In a college,$150$ students of $MBA$ are enrolled. The ratio of boys to girls is $7:8$. There are three disciplines in the college: Marketing,$HR$,and Finance. In the Marketing discipline,there are $50\%$ girls of their total number and the boys are $40\%$ of their total number. In the $HR$ discipline,girls are $30\%$ of their total number while boys are $30\%$ of their total number. The Finance discipline has girls $20\%$ of their total number and the boys are $30\%$ of their total number. $7$ boys and $9$ girls are in $HR$ and Marketing both. $6$ boys and $7$ girls are in $HR$ and Finance both. $5$ boys and $8$ girls are in Marketing and Finance both. $2$ boys and $3$ girls are enrolled in all the three disciplines. By what percent is the number of boys in the Marketing discipline more than the number of girls in the $HR$ discipline?

In a family,the ratio of expenses to savings is $5:3$. If the expenses increase by $60\%$ and the income increases by $25\%$,the savings decrease by $Rs. 3500$. Find the increased income (in $Rs.$) of the family.

If $3 A = 6 B = 9 C$,what is $A : B : C$?