a + b + c = x
a = 30x/100
b = (x - a) * 60/100 = (x - 30x/100) * 60/100 =
420x/100 : 10 =
420x/100 * 1/10 =
42x/100
c = 336 km
30x/100 + 42x/100 + 336 = x
30x + 42x + 33600 = 100x
72x + 33600 = 100x
28x = 33600
x = 33600 : 28
x = 1200 km lungimea drumului
a = 30x/100 =30 * 1200/100
a = 360 km prima zi
1200 - 360 = 840 km rest
b = 840 * 60/100
b = 504 km a doua zi
c = 336 km