Rice

Rice wants three things: rice, water and salt, and one thing more, which is time. For every cup of rice take a cup and a half of water and half a teaspoon of salt.

Rice $=$ rice $+$ water $+$ salt $+$ time. Per $1$ cup rice: $1.5$ cups water, $\frac{1}{2}$ tsp salt. Water/rice $=1.5$.

rice $=f(R,W,S,t)$ ($R$ rice, $W$ water, $S$ salt, $t$ time). $R:W:S=1:1.5:\frac{1}{2}$ (cup, cup, tsp).

Rinse the rice three or four times, until the water runs clear, then let it soak for half an hour. Soaked rice cooks evenly; unsoaked rice is soft outside and hard inside.

Rinse $3$ or $4$ times, until clear; soak $30$ min. Soaked $\Rightarrow$ even; unsoaked $\Rightarrow$ soft outside, hard inside.

rinse $\times 3$ or $4\to$ soak $30^{\prime }$. soak $\Rightarrow$ even; $\neg$soak $\Rightarrow$ out soft, in hard.

Bring the water to the boil, add the salt and the rice, and when it boils again turn the heat right down and put the lid on. Twenty minutes, and do not lift the lid.

Boil the water; add salt and rice; boils again $\Rightarrow$ heat to the minimum, lid on. $20$ min, lid stays on.

boil$(W)\to +S,+R\to$ boil $\Rightarrow$ heat $\to \min$, lid on $20^{\prime }$.

Turn off the heat and leave it for ten more minutes. The grains finish cooking in their own steam.

Heat off; wait $10$ min. The grains finish in their own steam.

heat $=0$; $10^{\prime }$. steam $\to$ grain.

Two cups of rice feed four people, because rice roughly triples when it cooks: two cups dry become about six cups cooked, a cup and a half each. For eight people double the rice and the water, but not the time.

$2$ cups rice feed $4$: cooked $\approx 3\times$ dry, so $2\to 6$ cups, $6/4=1.5$ cups each. For $8$ people: $2\times$ the rice and water, $1\times$ the time.

$R=2\Rightarrow$ feeds $4$: $V_1\approx 3V_0=6$ cups ($V_0$ dry), $6/4=1.5$ each. $n$ people: $R,W\propto n$; $t/\propto n$.