Fie x lungimea traseului
In prima zi a parcurs [tex] \frac{30}{100}x [/tex]
A doua zi a parcurs [tex] \frac{30}{100}(x- \frac{3}{10} x)= \frac{3}{10} \frac{7}{10}x= \frac{21}{100} x [/tex]
3/10x +21/100x+ 147 =x
30x +21x +14700= 100x
49x=14700 ⇒ x=300 km
b) a doua zi a parcurs 3/10·300=90 km