Answer:
3 packages
Step-by-step explanation:
There are 1000 m in 1 km, so 2500 m is the same as 2.5 km.
1 package = 2.5 km
2 packages = 5.0 km . . . . still too little
3 packages = 7.5 km . . . . more than sufficient
Annabelle needs 3 packages of yarn to satisfy her requirement for 7 km.