The wording "the amount of water required for different amounts of rice" suggests that the "output" value of the table is the amount of water, and the "input" value is the amount of rice.
That makes "water" the <em>dependent</em> variable, and "rice" the <em>independent</em> variable.
Since he wants to buy a game system you can also write this as an inequality, if the amount of the game system has any relevance in the problem. 8.25*H >= 206.25
