An airline company has been contracting a maintenance company to do overhauls for its planes at a cost of $55602 per plane per quarter. The airline company estimates that by building a $3241539 maintenance facility with a life of 5 years and a residual market value of $480964 at the end of its life, they could handle their own overhaul at a cost of only $23501 per plane per quarter. What is the minimum number of planes they must operate to make it just profitable to build this facility? (r = 8%, compounded quarterly). Select one: 3 06 05 22 28