Find two numbers whose $AM+...$ Find two numbers whose $AM + GM =25$ and $AM:GM=5:3$.

My Attempt;

Given,
$\frac {AM}{GM}=\frac {5}{3} = k (let) $
$\AM=5k,
GM=3k$.

Also,
$AM+GM=25$
$5k+3k=25$
$8k=25$
$k=\frac {25}{8}$.

Am I going right? Or, is there any other simple alternative.?
Your process of working has so far been correct, but there is still work to do.

Substituting we have AM=$\frac {a+b}{2}=\frac {125}{8} $ and GM=$\sqrt {ab}=\frac {75}{8} $ where $a $ and $b $ are the two numbers. Thus, find $(a-b) $ from the relation $$(a-b)=\sqrt {(a+b)^2-4ab} $$ and solve for the numbers. Hope it helps.
we have $$AM=\frac{5}{3}GM$$ from here we get with the first equation:
$$\frac{5}{3}GM+GM=25$$ thus we have $$\frac{8}{3}GM=25$$ and $$GM=\frac{75}{8}$$
from here we get $$ab=\left(\frac{75}{8}\right)^2$$ and $$a+b=\frac{375}{12}$$ you can solve one equation e.g. for $a$ and plug these equation in the other one
ok with $$b=\frac{375}{12}-a$$ we get
$$a\left(\frac{375}{12}-a\right)=\left(\frac{75}{8}\right)^2$$
this is equivalent to $$0=a^2-\frac{375}{12}a+\left(\frac{75}{8}\right)^2$$
solveing this we get $$a=\frac{225}{8}$$ or $$a=\frac{25}{8}$$