Elle placed a bucket under a leaky roof. the bucket was 2/5 full after one-half hour. what is the rate in buckets per hour

Generally speaking, a rate is a ratio of an amount with respect to time. In this case, it is the ratio of buckets to time in hours. Assuming the rate is constant, then the solution for this problem is as follows:

Rate = 2/5 bucket ÷ 1/2 hour
Rate = 0.8 bucket/hour