### Home > CCA2 > Chapter 7 > Lesson 7.1.2 > Problem7-32

7-32.

Mary has an antique marble collection containing $40$ marbles.  She has five more red marbles than blue and twice as many red as green marbles.  Write a system of equations to find the number of each color of marble.

Let $b=$ the number of blue marbles, $r=$ the number of red marbles,
and $g=$ the number of green marbles.

$b+5=r\\2g=r\\r+g+b=40$

Solve the system of equations using a combination of substitution and elimination.