Tourists were on a hiking trip for three days. On the first day, they hiked 1/8 of the trail. On the second day they hiked 4/7 of the remaining trail. On the third day they hiked 1/3 of the remaining trail and the last 8 km. How many km is the whole trail?

Let x = the length (km) of the whole trail.

1st day:

(1/8) x = 0.125x traveled.

Remaining amount = (1 - 0.125) x = 0.875x

2nd day:

(4/7) of 0.875x = 0.5x traveled.

Remaining amount = (1 - 0.5) x = 0.5x

3rd day:

(1/3) of 0.5x = 0.1667x traveled + 8 km

The total fractional parts traveled is

0.125x + 0.5x + 0.1667x = 0.7917x

The remaining fractional shares is (1 - 0.7917) x = 0.2083x.

This is equal to the 8 km traveled, therefore

0.2083x = 8

x = 8/0.2083 = 38.406 km

Answer: 38.4 km (nearest tenth)