Question

Un excursionist a strabatut 21/90 din intregul traseu, a doua zi 125/100 din cat a parcurs in prima zi si i-au ramas 285 km. Care este lungimea traseului ?

Answer 1

21X/90+125/100(21x/90)+285

7x/30+5/4(7x/30)+285=x

4*7x+5*7x+120*285=120x

120*285=120x-35x-28x

120*285=57x

x=(120*285)/57

 x=600 km
Verificare
prima zi 21/90 din 600=  7/30*600=140 km
zi a 3 a 285 km
zi a 2 a 600-140-285=175km  sau  125/100(21x/90)⇒  5/4*7x/30 dar x=600
5/4*140=1,25*140=175 km

total 
140+475+285=600
600=600