Respuesta :
It would be [tex]\frac{10}{38}[/tex], or, in simplest form, [tex]\frac{5}{19}[/tex].
You get this by adding all the marbles to find the total number of marbles. 10+7+12+9, which equals 38.
You have 10 red marbles out of 38 total, so that is represented by [tex]\frac{10}{38}[/tex]!