A box of Brand A laundry detergent washes 20 loads of laundry and costs $6. A box of Brand B laundry detergent washes 15 loads of laundry and costs $5.

Question

In the ratio tables that follow, fill in equivalent rates of loads washed per dollar. Include some examples where the number of loads washed is less than 15 and the cost is less than $5. Explain your reasoning.
For Brand A, the top is 20 loads and the bottom is $6.
For Brand B, the top is 25 loads and the bottom is $5.

Let's say for Brand A, I have 20 loads and it costs $6, the next load will be 3.33 that costs $1. How would I keep going to find the next load and the costs of that load? For Brand B, I have 15 loads that costs $5 and the next load is 3 that costs $1, how would I find the next loads and costs?
For Brand A: loads washed is 20 divided by 6 to get to the next load which is 3.33 and the costs is $6 divided by 6 which is 1. So the next load is 3.33 that costs $1. For Brand A: loads washed is 20 divided by 20 to get to the next load which is 1 and the costs is $6 divided by 20 which is $0.30. So the next load is 1 that costs $0.30
For Brand B: loads washed is 15 divided by 5 to get to the next load which is 3 and the costs is $5 divided by 5 which is $1. So the next load is 3 that costs $1. For Brand A: loads washed is 15 divided by 15 to get to the next load which is 1 and the costs is $5 divided by 15 which is $0.33. So the next load is 1 that costs $0.33
How would I keep going where the number of loads washed is less than 15 and the cost is less than $5