1. ## counting problem

Johnny has 76 solid-colored disks that are either red, green, or blue. He lines them up on the floor and finds that there are 4 more red disks that green and 6 more green disks than blue. How many red disks does he have?

Not sure how they're getting 30?

2. Originally Posted by mjoshua
Johnny has 76 solid-colored disks that are either red, green, or blue. He lines them up on the floor and finds that there are 4 more red disks that green and 6 more green disks than blue. How many red disks does he have?

Not sure how they're getting 30?
let r= Red disks
g= green disks
and b = blue disks.

then $\displaystyle r+g+b=76$

there are 4 more red disks that green means: $\displaystyle r = g+4$

6 more green disks than blue means: $\displaystyle g = b+6$

from the above equation,you can also write $\displaystyle b=g-6$

so $\displaystyle r+g+b=76$

or, $\displaystyle (g+4)+g+(g-6) = 76$

that gives you $\displaystyle g = 26$

and you know that $\displaystyle r = g+4=26+4=30$

you can also find out how many blue disks are there.. add the numbers up and you should get 76