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):

What should be subtracted from $15, 28, 20,$ and $38$ so that the remaining numbers are in proportion?

If $x: y = 5: 2,$ then $(8x + 9y) : (8x + 2y)$ is

What is the value of $68 \%$ of two-fifths of $550$?

The speeds of three cars are in the ratio of $1: 3: 5$. The ratio among the time taken by these cars to travel the same distance is

Out of the number of qualified candidates from State $P$ in $2008,$ the respective ratio of male and female candidates is $11: 7.$ If the number of female qualified candidates from State $P$ in $2008$ is $126,$ what is the total number of qualified candidates (both male and female) from State $P$ in $2008?$