Relation between ratio and percentage I would like to know easiest method to solve following:
Que: 
If $p$ is $128$% of $r$, $q$ is $96$% of $r$ and $r$ is $250$% of $s$, find the ratio of $p$:$q$:$s$.
My Approach:
Step 1: 
$p =\frac{128r}{100}$
$q = \frac{96r}{100}$
$r = \frac{250s}{100}$
So, $s = \frac{100r}{250}$
I do not know what to do further. 
I know the answer but don't know how to achieve Ans: $16$:$12$:$5$
Thank You!
 A: s is 40% of r, divide everything in units of 8% of r.
A: Substitute third equation ($r = 2.5s$) into first and second equations.
That will give you ratio of p:s and q:s.
Now either substitute first equation into second or vice versa. That will give you p:q.
Last step is to make sure that the ratio's are given in integers (so for example $1:2$ instead of $\frac{1}{2} :1$). Note, you are doing it only for readability of the text.
A: You have:


*

*$\frac{p}{r}=\frac{128}{100}$

*$\frac{q}{r}=\frac{ 96}{100}$

*$\frac{s}{r}=\frac{100}{250}$


Adjust them to the same denominator:


*

*$\frac{p}{r}=\frac{128}{100}\times\frac55=\frac{640}{500}$

*$\frac{q}{r}=\frac{ 96}{100}\times\frac55=\frac{480}{500}$

*$\frac{s}{r}=\frac{100}{250}\times\frac22=\frac{200}{500}$


And you get $p:q:s=640:480:200$.
Divide each factor by their greatest common divisor ($40$).
And you get $p:q:s=640/40:480/40:200/40=16:12:5$.
A: Notice, $p, q, r$ all depend on $s$ as follows  $$r=\frac{250}{100}\times s=\frac{250s}{100}$$ 
$$q=\frac{96}{100}\times r=\frac{96}{100}\times \frac{250s}{100}$$ 
$$p=\frac{128}{100}\times r=\frac{128}{100}\times \frac{250s}{100}$$ 
hence, $$\color{red}{p:q:s}=\left(\frac{128}{100}\times \frac{250s}{100}\right):\left(\frac{96}{100}\times \frac{250s}{100}\right):(s)$$ $$=128:96:40$$
$$=\color{red}{16:12:5}$$
