Answer:
The ratio is 6:2:1.
Explanation:
Let's denote:
Blue counter b
Red counter r
Yellow counter y.
There is given
r=3b (three times more red as blue) [1]
and
b=2y (twice more blue as yellow.) [2]
Now, replacing [2] to [1] gives
3*2y=r
6y=r.
Hence, the ratio is 6:2:1, because r=6y and b=2y.