Bal qiyaas laba koob oo isku mid ah - mid ka buuxa qaxwo iyo kan kale oo caano ah, labaduba waa isku heer. Qaado qaxwo ah ayaa hadda laga soo qaaday koobkii kafeega oo lagu shubay koobka caanaha oo la walaaqay. Dabadeed ku dar shaaha isku dhafka ah ee koobkii caanaha ku celi koobkii qaxwaha. Koobkee ka kooban dareere shisheeye oo badan?
Dareen ahaan, waxaa laga yaabaa in qofku u maleynayo in uu jiro qaxwo badan oo ku jira koobka caanaha sababtoo ah shaaha ugu horreeya ayaa ka kooban qaxwo oo keliya, halka shaaha dib loo qaaday uu ahaa caano iyo qaxwo isku dhafan. Jawaabta la yaabka leh ayaa ah in labada koobba ay ku dhammaadaan qaddar isku mid ah oo dareere shisheeye ah. Si tan loo sameeyo, xadiga kafeega iyo caanaha waxaa lagu falanqeeyaa seddex dhibcood waqti \(t_0, t_1, t_2\):
- \(t_0\) (bilawga): Koob kafee ah oo buuxa ( \(T\) ) oo aan caano lahayn ( \(0\) \(0\) ) koobka qaxwaha, kafee maya caanaha ( \(T\) ) ee koobka caanaha.
- \(t_1\) (wareejinta koowaad ka dib): \(TL\) qaxwo iyo \(0\) caanaha ku jira koob kafeega, \(L\) kafeega iyo \(T\) caanaha ku jira koobka caanaha ( \(L\) = shaaha tirada)
- \(t_2\) (wareejinta labaad ka dib): \(T-L+L_2\) qaxwo iyo \(L_1\) caanaha ku jira koob kafeega, \(L-L_2\) kafeega iyo \(T-L_1\) caanaha koobka caanaha ( \(L_1\) = xadiga caanaha shaaha, \(L_2\) = xadiga kafeega ee shaaha).
Tan iyo \(L_1+L_2 = L\) , \(L-L_2 = L_1\) . Taas macneheedu waxa weeye in xadiga caanaha ( \(L_1\) ) ee ku jira koobka kafeega ay la mid yihiin xadiga kafeega ( \(L-L_2\) ) ee koobka caanaha. Tan waxaa si cad loo sharxi karaa sida soo socota: Dhamaadka tijaabada, koobka qaxwaha ayaa la mid ah heerka bilowga. Laakiin mar haddii caano lagu daray, kafeega kafeega ahi waa inuu ka baxaa koobka. Intan kafeega ah ayaa hadda ku jirta koobka caanaha.