Aplicando los tres casos con la regla de tres :
<img src="https://tex.z-dn.net/?f=40l------780km%5C%5C%0A5l--------%3E5l.780km%2F40l%3D97%2C5km" />5l.
780km / 40l = 97, 5km" alt = "40l - - - - - - 780km \ \ 
 ; 5l - - - - - - - - >5l.
780km / 40l = 97, 5km" align = "absmiddle" class = "latex - formula">
<img src="https://tex.z-dn.net/?f=40l------780km%5C%5C10l------%3E10l.780km%2F40l%3D195km" />10l.
780km / 40l = 195km" alt = "40l - - - - - - 780km \ \ 10l - - - - - - >10l.
780km / 40l = 195km" align = "absmiddle" class = "latex - formula">
<img src="https://tex.z-dn.net/?f=40l-----780km%5C%5C25l------%3E25l.780km%2F40l%3D487%2C5km" />25l.
780km / 40l = 487, 5km" alt = "40l - - - - - 780km \ \ 25l - - - - - - >25l.
780km / 40l = 487, 5km" align = "absmiddle" class = "latex - formula">
Saludos.