A new highway is to be constructed. Design A calls for a concrete pavement costing $90 per foot with a 12-year life; two paved ditches costing $4 per foot each; and four box culverts every mile, each costing $10,000 and having a 12-year life. Annual maintenance will cost $1,600 per mile; the culverts must be cleaned every three years at a cost of $550 each per mile. Design B calls for a bituminous pavement costing $45 per foot with a 6-year life; two sodded ditches costing $1.55 per foot each; and two pipe culverts every mile, each costing $2,150 and having a 6-year life. The replacement culverts will cost $2,450each. Annual maintenance will cost $2,700 per mile; the culverts must be cleaned yearly at a cost of $215 each per mile; and the annual ditch maintenance will cost $1.45 per foot per ditch. Compare the two designs on the basis of equivalent worth per mile for a 12-year period. Find the most economical design on the basis of AW and PW if the MARR is 12%per year