Question

Un biciclist are de parcurs un drum in 3 zile. In prima zi parcurge unu pe patru din drum, a doua zi parcurge unu pe doi din rest si a treia zi parcure 18 km. Cati km. are drumul? Cati km. a parcurs in fiecare zi ?

Answer 1

rezolvarea in arasament

Answer 2

in prima zi parcurge: 1/4 din x
a doua zi parcurge 1/2 din(x-x/4)
a treia zi 18 km
total parcurs in 3 zile :
$x= \frac{x}{4}+ \frac{1}{2}(x- \frac{x}{4}) +18$
$x= \frac{x}{4}+ \frac{x}{2}- \frac{x}{8} +18 \\ \\ 8*x=x*2+x*4-x+18*8 \\ \\ 8x-2x-4x+x=18*8 \\ \\ 3x=18*8 \\ \\ x=48$
drumul are 48 km
in prima zi parcurge: 1/4 din x  adica 48:4=12 km
a doua zi parcurge 1/2 din(x-x/4) $\frac{1}{2}(x- \frac{x}{4} )= \frac{1}{2}(48- \frac{48}{4})= \frac{1}{2}(48-12)= \frac{1}{2} *36= \frac{36}{2}=18 km$
a treia zi 18 km