A new highway is to be constructed. Design A calls for a concrete pavement costing $80 per foot with a 20-year life; four paved ditches costing 53 per foot each; and two box culverts every mile, each costing $7,000 and having a 20-year life. Annual maintenance will cost $1,600 per mile; the culverts must be cleaned every five years at a cost of $500 each per mile. Design B calls for a bituminous pavement costing $30 per foot with a 10-year life; two sodded ditches costing $1.65 per foot each; and four pipe culverts every mile, each costing $2,250 and having a 10-year life. The replacement culverts will cost $2,450 each. Annual maintenance will cost $2,700 per mile; the culverts must be cleaned yearly at a cost of $225 each per mile; and the annual ditch maintenance will cost $1.40 per foot per ditch. Compare the two designs on the basis of equivalent worth per mile for a 20-year period. Find the most economical design on the basis of AW and PW if the MARR is 6% per year. Click the icon to view the interest and annuity table for discrete compounding when the MARR is 6% per year. The AW value for Design A is $ mi. (Round to the nearest hundreds.) The PW value for Design A is $/mi. (Round to the nearest hundreds.) The AW value for Design B is $/mi. (Round to the nearest hundreds.) The PW value for Design B is $/mi. (Round to the nearest hundreds.) The most economical design on the basis of AW and PW is