math
posted by Mai on .
There are fifty marbles in a
sack: red, blue and green.
There are ten more green
than blue marbles in the
sack. The probability of
drawing a red or blue marble
is onehalf. Write and solve
an equation to determine
how many of each color
marble is in the sack

"The probability of
drawing a red or blue marble
is onehalf."
Means that Red+Blue=half * 50 = 25.
Can you do the rest? 
i don't know if i can do it...

Known facts:
Red+Blue+Green=50
Red+Blue=25
GreenBlue=10
Can you juggle a little with the above equations to come up with the answer? 
so there be 25 green, 15 blue, 10 red???

Correct, good job!