Given that,
- $p:q = 1:2$
- $q:r = 4:3$
- $r:s = 4:5$
Let, $p:q = 1:2 = k \Rightarrow \boxed{p = k,q = 2k}$
And, $r:s = 4;5 = k \Rightarrow \boxed{r = 4k, s = 5k}$
Now, $u = 5k \times 1.5 = 7.5k$
$\therefore $ The ratio of $p:u = k:7.5k = 1:7.5 = 2:15.$
Correct Answer $:\text{A}$
${\color{Green}{\textbf{PS:} \; \text{If}\;x \;\text{is}\; 50\%\;\text{more than}\; 100 \Rightarrow x = 100 + 100 \times \frac{50}{100} = 150.}}$