Răspuns :
x= lungimea drumului
prima zi : 3x/8
a doua zi : 2/5 * (x - 3x/8 ) +9 = 2/5*( 8x/8-3x/8) +9= 2/5* 5x/8 +9
a treia zi : 27
Prima zi + a doua zi + a traia zi = x
3x/8 + 10x/40 +9+27 = x
15x/40 + 10x/40 +36 = x
25x/40 +36=x
36 = 40x/40 - 25x/40
36=15x/40
36*40 = 15x
1440 = 15x
x=1440 :15
x= 96 km
prima zi : 3x/8
a doua zi : 2/5 * (x - 3x/8 ) +9 = 2/5*( 8x/8-3x/8) +9= 2/5* 5x/8 +9
a treia zi : 27
Prima zi + a doua zi + a traia zi = x
3x/8 + 10x/40 +9+27 = x
15x/40 + 10x/40 +36 = x
25x/40 +36=x
36 = 40x/40 - 25x/40
36=15x/40
36*40 = 15x
1440 = 15x
x=1440 :15
x= 96 km