An airline company has been contracting a maintenance company to do overhauls for its planes at a cost of $66278 per plane per quarter. The airline company estimates that by building a $4090055 maintenance facility with a life of 5 years and a residual market value of $424171 at the end of its life, they could handle their own overhaul at a cost of only $43360 per plane per quarter. What is the minimum number of planes they must operate to make it just profitable to build this facility? (i=2% per quarter). 51 10 9 4 41