If $A: B = 7: 5$ and $B: C = 9: 11,$ then $A: B: C$ is equal to

$15$ litres of mixture contains $20 \%$ alcohol and the rest water. If $3$ litres of water be mixed with it,the percentage of alcohol in the new mixture would be:

₹ $73,689$ are divided between $A$ and $B$ in the ratio $4:7$. What is the difference between thrice the share of $A$ and twice the share of $B$? (In ₹)

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,namely,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 the $HR$ and Marketing both. $6$ boys and $7$ girls are in the $HR$ and Finance both. $5$ boys and $8$ girls are in the Marketing and Finance both. $2$ boys and $3$ girls are enrolled in all the three disciplines. What percentage of students are enrolled in all three disciplines?

$A$ box of sweets was distributed between $A$ and $B$ in the ratio $3:4$. If $A$ got $36$ sweets,what was the total number of sweets?

Find the compound ratio of $2:7$,$5:3$,and $4:7$.