To solve this question, you divide the number of tofu required with the number of tofu own. Stephen uses 2/25 kilograms of tofu in each serving and he has 1+1/10 kilograms tofu. The calculation would be:
(1+1/10) / (2/25)=
(11/10)/(2/25)=
11/10 * 25/2=
275/20= 13.75 servings