A. 1/1/2 cups
Explanation:
So we know:
2/3 cup of sunflower seeds = 4 cups of trail mix
We need to find:
? cups of sunflower seeds = 9 cups of trail mix
Firstly, we find how many cup of seeds for 1 cup of trail mix:
? cup of sunflower seeds = 1 cup of trail mix
This we do by:
2/3 ÷ 4 = 1/6
so now we got,
1/6 cups of sunflower seeds = 1 cup of trail mix
now multiply by what we need to find (the 9 cups of trail mix) so the full answer will be
2/3 ÷ 4 = 1/6
1/6 x 9 = 1/1/2