Addition and Subtraction of Decimal Fractions

The sum of $\frac{1}{9}, \frac{1}{3}, \frac{1}{6}$ and $\frac{7}{18}$ of a number is $150$. The number is:

The sum of $\frac{1}{2},\frac{1}{4}$ and $\frac{1}{8}$ of a number is $28$. The number is:

A number, one-sixth of which exceeds its one-ninth by $100$ is:

What will come at place of question mark(?) in the following fraction, 

$\frac{1}{15}+\frac{3}{15}+\frac{5}{15}+\frac{6}{15}=?$

Which fraction should be added to the sum of $5\frac{3}{4}, 4\frac{4}{5}$ and $7\frac{3}{8}$ to make the result a whole number?

A number, the sum of whose fourth and fifth parts exceeds their third part by $28$, is:

If $21$ is added to four times a number, the result is $57$. The number is:

The number less than $15$ by $7$ is:

Five times $y$ diminished by $20$ is equal to:

Six times $x$ is increased by $12$ is equal to: