Response to the following problem:
Garber plumbers offers a 20% trade discount when providing $2000 or more of plumbing services to its customers. In march 2012, garber provided $4000 of plumbing services to red oak, inc. and $1500 of services to cyril, inc. Each of these customers was granted credit terms of 2/10, net 30. if both customers paid for the plumbing services within the discount period, what was the net sales figure for these two transactions?
Provide step by step calculations.