If she uses 2 bags of soil for 6 plants, that would mean that she is using 1 bag per 3 plants. Therefore if she was planting 15 plants, she would use 5 bags of soil.
If she uses 2 bags of soil for 6 plants, that would mean that she is using 1 bag per 3 plants. Therefore if she was planting 15 plants, she would use 5 bags of soil.
