Answer:
6 lbs of fertilizer
Explanation:
Since 4 lbs of fertilizer can be used for 120 sq ft of soil, we can calculate how many sq ft 1 lbs of fertilizer can cover
1 lbs of fertilizer = 120/4 = 30 sq ft of soil
From this, we can find how many lbs of fertilizer is needed for 180 sq ft of soil
180/30 = 6 lbs of fertilizer