The fourth proportional to $5, 8, 15$ is

If two-third of $A$ is four-fifth of $B ,$ then $A : B =?$

The sum of the present ages of a father and his son is $90$ years. $10$ years ago,the ratio of their ages was $5:2$. The present age of the father is (in years):

Amit,Sumit and Puneet share an amount of ₹ $660$ in the ratio of $3: 4: 5$. What is the share of Puneet (in ₹)?

The ratio of the number of boys and girls in a college is $7:8$. If the percentage increase in the number of boys and girls is $20\%$ and $10\%$ respectively,what will be the new ratio?

The ratio of the number of boys and girls in a school is $8: 12$. If $50 \%$ of boys and $25 \%$ of girls are getting scholarships for their studies,what is the percentage of school students who are not getting any scholarships (in $\%$)?