Dear Gabrielle;

Hi,

To obtain a soil containing 18.67% of water, we had to dissolve in 18.67 mL of water in 100–18.67= 81.33 grams of soil. Now how much water should be dissolved in 1200 gram of soil? Obtain: 275.47 ml of water.

Sincerely yours;

Saeed

Dear Gabrielle,

let 1200 g of dry soil be 100% - 18.76% water = 81.33% dry soil.

According to the rule of proportion, 18.76% = 275.47 g water to be added:

1200 g + 275.47 g = 1475.47 g (100%) resulting wet soil.

By the way, I used to teach Arnis, Philippino martial arts, at UST several years ago, together with late Great Grandmaster Ernesto A Presas, sen.

Wishing you best of success,

Johannes

I agree with @ Johannes Haedrich answer;