A) 1 cm = 3.5 km
The trail is 8cm long on the map, multiply 8 by 3.5:
8 x 3.5 = 28 km total
B. The first map is 8cm, the second map is 5 cm
The scale factor to change from the 1st map to the 2nd map would be 5/8
Multiply the dimensions on the 1st map by 5/8.
3 cm x 5/8 = 1 7/8 cm
4 cm x 5/8 = 2 1/2 cm
6 cm x 5/8 = 3 3/4 cm