Question

Un ciclist are de parcurs un traseu.In prima zi parcurge 1/3 din traseu.A doua zi parcurge 1/4 din traseul ramas. Atreia zi parcurge 2/5 din noul rest, iar in a parta zi ultimii 72 de kilometri.Ce lungime are traseul?

Answer 1

prima zi⇒1/3·y=y/3;
⇒a ramas=y-y/3=3y/3-y/3=2y/3;
⇒a doua zi⇒1/4·2y/3=1/2·y/6=y/12;
⇒a ramas 2y/3-y/12
⇒8y/12-y/12=7y/12;
⇒a treia zi⇒2/5·7y/12
⇒1/5·7y/6⇒7y/30;
⇒a ramas=7y/12-7y/30
⇒35y/160-14y/60
⇒21y/60
⇒7y/20
⇒7y/20=72km
⇒y=20·72km/7
⇒y=205,714285km[lungimea traseului];