Nadia walked 18 kilometers, which was twice as far as Hannah walked. How many kilometers did the two girls walk in total?
How far did Hannah walk? ** Hannah = (1/2) 18 = 9
How far did Hannah and Nadia walk? ** 9 + 18 = <<9+18=27>>27 km
How many kilometers did the two girls walk in total? ** Together they walked 27 kilometers.
#### 27