340. From the formulas $l=v t ; v=\frac{l}{t} ; t=\frac{l}{v}$ (where $l$ represents the distance traveled over time $t$ by a body moving uniformly at speed $v$), determine which of these quantities are directly proportional to each other and which are inversely proportional (assuming the third quantity remains unchanged)?
340. Two quantities are directly proportional when their quotient is constant; they are inversely proportional when their product is constant. Thus: $l$ and $v, l$ and $t$ are directly proportional, $v$ and $t$ are inversely proportional.