Răspuns :
a = lungimea drumului
I et = a/4 + 6
II et = 1/3(a - a/4 - 6) + 4 = 1/3(3a/4 - 6) + 4 = a/4 - 2 + 4 = a/4 + 2
III et = 1/2 (a - a/4 - 6 - a/4 - 2) + 10 = 1/2(2a/4 -8) + 10 = a/4 -4+10 = a/4+6
a/4 + 6 + a/4 + 2 + a/4 + 6 + 42 = a
3a/4 + 56 = a /x4
3a + 224 = 4a
224 = 4a - 3a
a = 224 km lungimea drumului
I et. = 224/4 + 6 = 56 + 6 = 62 km
II et = 224/4 + 2 = 56 + 2 = 58 km
III et = 224/4 + 6 = 56 + 6 = 62 km
IV et = 42 km
62 + 58 + 62 + 42 = 224 km
I et = a/4 + 6
II et = 1/3(a - a/4 - 6) + 4 = 1/3(3a/4 - 6) + 4 = a/4 - 2 + 4 = a/4 + 2
III et = 1/2 (a - a/4 - 6 - a/4 - 2) + 10 = 1/2(2a/4 -8) + 10 = a/4 -4+10 = a/4+6
a/4 + 6 + a/4 + 2 + a/4 + 6 + 42 = a
3a/4 + 56 = a /x4
3a + 224 = 4a
224 = 4a - 3a
a = 224 km lungimea drumului
I et. = 224/4 + 6 = 56 + 6 = 62 km
II et = 224/4 + 2 = 56 + 2 = 58 km
III et = 224/4 + 6 = 56 + 6 = 62 km
IV et = 42 km
62 + 58 + 62 + 42 = 224 km